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Interstate 25

Interstate 25 (I-25) is a major north–south Interstate Highway in the that extends 1,060.97 miles (1,707.79 km) from an interchange with in , to an interchange with Interstate 90 in . The route traverses three states— for 462.12 miles (743.96 km), for 298.60 miles (480.61 km), and for 300.25 miles (483.22 km)—primarily following the eastern front of the and serving as the principal north-south corridor through the region. I-25 connects key urban areas, including Las Cruces and Albuquerque in ; Pueblo, Colorado Springs, and in ; and Cheyenne and Casper in . It passes near the state capitals of ; ; and , facilitating interstate travel along the densely populated . As the only Interstate highway running north-south through , I-25 supports critical commercial freight movement, tourism to Rocky Mountain destinations, and daily commuting in one of the fastest-growing corridors in the country. The highway's completion in Colorado occurred on September 21, 1969, after construction that spanned over a decade and cost $125 million.

Route description

New Mexico

Interstate 25 in spans approximately 462 miles from its southern terminus at in Las Cruces to the state line north of Raton, with exits numbered sequentially from 0 to 460 based on mileposts. I-25 begins at a major interchange with I-10 in Las Cruces, heading north through rural desert areas, passing near and Elephant Butte Lake State Park. It traverses the Rio Grande Valley, serving Socorro and before entering the urban , where it crosses I-40 at the Big I interchange. North of Albuquerque, the route passes through Bernalillo and several lands, then climbs toward , the state capital, via a bypass (NM 599). Continuing northeast, it goes through and Raton, ascending to the state line. The highway follows the historic corridor in parts, with increasing elevation and mountainous terrain near the end. The following table lists all exits along I-25 in New Mexico, compiled from northbound configurations (which generally apply bidirectionally unless noted), including exit numbers, approximate mile markers where available, primary destinations served, and brief notes on significance such as services, restrictions, or traffic volume.
ExitMileDestinations (Northbound/Southbound)Notes
00I-10 E/W – Las Cruces, Deming, El Paso TXSouthern terminus; major interstate junction.
11NM 292 – University Ave, Las CrucesAccess to New Mexico State University; key local entry.
33Lohman Ave – Las CrucesCommercial area with fuel and food services.
66US 70 E – Alamogordo, Del Rey BlvdEastward connection to White Sands Missile Range.
99NM 320 – Dona AnaRural access; limited services.
1919Radium SpringsScenic area near Rio Grande; rest area nearby.
3232County Road E071 – RinconTruck turnout available.
3535NM 140 – Hatch, RinconAgricultural region; US Border Patrol checkpoint.
4141NM 26 W – HatchLocal town access.
5151NM 546 – Garfield, SalemRural farming area.
5959NM 187 – Caballo, Percha State ParksAccess to Elephant Butte Lake recreation.
6363NM 152 – HillsboroConnection to mining historic sites.
7171Las PalomasLimited rural access.
7575Williamsburg, Truth or ConsequencesBusiness loop entry.
7979I-25 BUS – Truth or ConsequencesTown center; US Border Patrol checkpoint.
8383Elephant Butte Lake State ParkMajor recreation area.
8989Martin Ranch Rd – Truth or ConsequencesLocal ranch access.
9292Mitchell PointScenic overlook.
100100Red RockState park access.
115115SR 107 – San Antonio, Camino Real International Heritage CenterHistoric trail site; rest area at mile 114.
124124SR 178 – Willow Springs Ranch RdRural.
139139US 380 E – San Antonio, CarrizozoEast-west connector.
147147US 60 W – Socorro, MagdalenaMajor east-west route.
150150US 60 W, I-25 BUS W – SocorroBusiness loop.
152152EscondidaLocal access.
156156NM 408 – LemitarRural.
163163San AcaciaRest area.
175175US 60 E – Bernardo, MountainairEastward to Salinas Pueblo Missions.
190190I-25 BUS – BelenSouth Belen access.
191191Camino Del Llano – BelenLocal.
195195BelenMain town entry.
203203NM 6 – Los LunasConnection to historic Route 66.
209209NM 317, NM 314, NM 45 – Isleta PuebloPueblo lands; high ADT approaching Albuquerque.
213213NM 314 – Isleta BlvdPueblo access.
215215NM 47 – AlbuquerqueRio Grande crossing; ADT exceeds 150,000 vehicles daily in urban core.
220220NM 500 – Rio Bravo BlvdSouth Albuquerque industrial.
221221Sunport Blvd – Albuquerque International SunportMajor airport; ADT around 204,000 in metro area.
222222Gibson Blvd – Kirtland AFBMilitary base; HOV lane evaluations in corridor.
223223Avenida Cesar Chavez – AlbuquerqueUniversity district.
224224Coal Ave, Lead Ave, Central Ave – AlbuquerqueDowntown access; high urban traffic.
225225Lomas Blvd, Menaul Blvd, Candelaria Rd – AlbuquerqueCentral city; ADT peaks at 204,000.
226226I-40 E/W – AlbuquerqueMajor junction with transcontinental interstate; Big I interchange.
227227Comanche Rd, Griegos Rd – AlbuquerqueNorth valley.
228228Montgomery Blvd, Montano Rd – AlbuquerqueCommercial corridor.
229229Jefferson St – AlbuquerqueLocal.
230230San Mateo Blvd, Osuna Rd – AlbuquerqueShopping areas.
231231Pan American Frontage Rd NBFrontage road access.
232232NM 423 – Paseo del Norte – AlbuquerqueNorthern suburbs.
233233Alameda Blvd, NM 528 – AlbuquerqueRio Grande access.
234234NM 556, Tramway Rd, Roy Ave – AlbuquerqueFoothills entry.
240240NM 473 – BernalilloTown center.
242242NM 165 E, US 550 W – Placitas, BernalilloJemez Mountains access.
248248NM 315 – AlgodonesLocal.
252252San Felipe PuebloTribal lands.
257257BudaghersRest area.
259259NM 22 – Santo Domingo PuebloPueblo access.
264264NM 16 – Cochiti PuebloHistoric sites.
267267Waldo, Canyon Rd – Santa FeSouthern approach to capital.
271271La Cienega, FM 50Local.
276276NM 599 S – MadridSanta Fe bypass.
278278NM 14 S/N – Madrid, Cerrillos Rd – Santa FeTurquoise Trail; city entry.
282A/B282US 84 N, US 285 N – St. Francis Dr, Santa Fe PlazaNorthern terminus of concurrency; tourist hub.
284284NM 466 – Old Pecos Trail – Santa FeHistoric route.
290290US 285 S – Clines CornersSouthward to I-40.
294294Sleeping Dog RdRural.
299299NM 50 – Glorieta, PecosGlorieta Pass historic battle site.
307307NM 63, NM 50 – Rowe, PecosLocal towns.
319319San Juan, San JoseRural.
323323NM 3 S – VillanuevaScenic byway.
330330BernalLocal.
339339US 84 S – Romeroville, Santa RosaWest to I-40.
343343NM 283, I-25 BUS, NM 329 – Las VegasTown entry.
345345NM 65, NM 104 – Las Vegas, University AveFort Union National Monument access.
347347I-25 Business, NM 250 – Las VegasBusiness loop.
352352Airport – Las VegasMunicipal airport.
356356Onava – Las VegasLocal.
361361Unnamed rural exitRural.
364364NM 161, NM 97 – Valmora, WatrousLocal.
366366NM 161, NM 97 – Watrous, ValmoraDuplicate access.
387387NM 120 – Wagon MoundEast-west connector.
393393LevyRural.
404404NM 569 – Colmor, MiamiLocal.
412412I-25 Business – SpringerTown loop.
414414SpringerMain entry.
419419NM 58 W – CimarronPhilmont Scout Ranch access.
426426NM 505 – MaxwellNational Wildlife Refuge.
435435Tinaja – RatonRural.
446446US 64 W – TaosConnection to Sangre de Cristo Mountains.
450450I-25 Business – RatonSouth Raton.
451451US 64 E, US 87 E – Clayton, RatonEastern plains; truck port of entry nearby at mile 460.
452452NM 72 E – Folsom, RatonCapulin Volcano access.
454454I-25 BUS, 2nd St – RatonDowntown Raton.
460460Colorado State LineNorthern terminus; Raton Pass elevation 7,834 ft; seasonal truck chain requirements possible.
Note: Destinations are primarily northbound but serve both directions; minor variations may exist for southbound ramps. HOV lanes are under evaluation in the Albuquerque corridor but not dedicated permanent facilities. Truck restrictions include inspections at Raton and potential winter chain laws in . Average daily traffic (ADT) in the Albuquerque area reaches up to 204,000 vehicles, establishing it as the busiest segment.

Colorado

Interstate 25 in features approximately 120 exits over its 298.87-mile length, from mile 0 at the state line near Trinidad to mile 299 at the state line north of Fort Collins. The interchanges vary significantly, with rural sections south of and north of Fort Collins exhibiting longer gaps between exits—often 10-20 miles—characterized by simple or partial cloverleaf designs to accommodate lower volumes and mountainous . In contrast, the urban corridor from to Fort Collins includes denser clustering of exits, with complex multi-level stack interchanges in major cities like and Colorado Springs to handle high congestion; average daily traffic (ADT) reaches peaks exceeding 250,000 vehicles in the metro area, necessitating innovations like managed express lanes and advanced interchange geometries. I-25 enters over near Trinidad, passing through Walsenburg and along the Front Range. It serves Colorado Springs with access to military bases like and the Air Force Academy, then continues north through Monument, Castle Rock, and the Denver suburbs, including the complex interchange with I-70. Beyond Denver, it traverses , Broomfield, and the northern suburbs to Fort Collins, connecting to rural areas in Larimer County before crossing into . Key highlights among these exits include Exit 2 near Trinidad, a serving CO 12 and local access to the historic town; Exit 214, —a five-level with I-70 in , rebuilt multiple times for seismic resilience and traffic efficiency following a 1984 structural incident; Exit 147 in Colorado Springs, a partial cloverleaf with US 24 (Cimarron Street) providing access to downtown and installations; and Exit 240 in Fort Collins, a trumpet-style interchange with US 287 (College Avenue), facilitating connectivity to and northern rural areas. Special notes on modern enhancements include diverging diamond interchanges (DDIs) introduced in the 2010s to reduce conflict points and delay, such as the one at Exit 100 with US 50 in (under construction, expected completion 2027) and at the Powers Boulevard/Airport Road surface intersection in Colorado Springs (ongoing as of 2025); additionally, reversible express lanes operate between Exits 207 (US 36) and 216 (), dynamically pricing tolls to optimize flow on segments with ADT over 200,000. The T-REX project in the early affected several Denver-area exits like 200 (I-225) by integrating , while terrain influences spacing, with fewer exits in the hilly region compared to the flat plains north of . The following table enumerates all exits, including number, approximate milepost, primary destinations/locations, and interchange type where documented (based on CDOT design standards favoring diamonds in rural areas and more complex forms urbanely).
ExitMileLocationsType
-0.00New Mexico state line (near Raton Pass)-
10.5County Road GG.5 – StarkvilleDiamond
22.0CO 12 – Trinidad, CokedaleDiamond
33.5CO 12 – Trinidad (northbound)Partial diamond
44.0Washington Street – TrinidadDiamond
55.5CO 71 – Starkville, AguilarDiamond
1111.0CO 10 – Ludlow, Trinidad State ParkDiamond
1212.0County Road 31.5 – LudlowPartial diamond
1515.0County Road 41.5 – GulnareDiamond
2020.0US 350 – Starkville, WestonDiamond
2525.0County Road 61.5 – TercioPartial diamond
2727.0CO 12 – Hoehne, MadridDiamond
3232.0County Road 70.8 – RinconDiamond
3737.0County Road FF – Aguilar vicinityPartial diamond
4242.0CO 69 – AguilarDiamond
4747.0County Road 41 – WalsenburgDiamond
5252.0I-25 Frontage Road – WalsenburgPartial diamond
5656.0CO 69 – Walsenburg, GardnerDiamond
5959.0US 160 – Walsenburg, Fort GarlandCloverleaf
6262.0County Road EE.5 – Gardner vicinityDiamond
6868.0CO 10 – La Veta, WalsenburgPartial diamond
7272.0County Road 520 – South Spanish Peak areaDiamond
7878.0US 160 – Fort Garland, AlamosaDiamond
8282.0County Road 21 – San Isabel National ForestPartial diamond
9090.0CO 69 – Rye, WetmoreDiamond
9494.0Pueblo BoulevardPartial cloverleaf
9696.0US 50 Bus. – PuebloDiamond
9898.0CO 45 – Pueblo BoulevardPartial diamond
100100.0US 50 – Pueblo (under construction, expected completion 2027)Diverging diamond
101101.0US 50 W – Cañon City, CO 47 E – Pueblo-
102102.0US 50 Bus. – Pueblo (Abilene Road)Diamond
104104.0CO 96 – PuebloCloverleaf
108108.0US 85 Bus. – Pueblo (Santa Fe Avenue)Partial diamond
110110.0CO 47 – Pueblo Memorial AirportDiamond
114114.0US 85/87 – PuebloPartial cloverleaf
116116.0CO 45 – Pueblo WestDiamond
118118.0US 85/87 – PenrosePartial diamond
123123.0CO 115 – Florence, PenroseDiamond
125125.0County Road 300 – FlorencePartial diamond
129129.0CO 120 – FlorenceDiamond
132132.0CO 16, CO 21 – Mesa Ridge Parkway, FountainDiamond
135135.0CO 85 – Security-WidefieldPartial diamond
138138.0CO 16 – StratmoorDiamond
140140.0CO 85 – Fort CarsonPartial cloverleaf
142142.0CO 85 – Lake Avenue, Colorado SpringsDiamond
144144.0US 24 Bus. – Colorado SpringsPartial diamond
145145.0CO 85 – Academy BoulevardDiamond
146146.0CO 85 – Platte AvenuePartial diamond
147147.0US 24 – Cimarron Street, Colorado SpringsPartial cloverleaf
148148.0CO 85 – Nevada AvenueDiamond
149149.0CO 85 – Tejon StreetPartial diamond
150150.0CO 85 – Union BoulevardDiamond
151151.0CO 85 – Union BoulevardDiamond
152152.0Woodmen RoadPartial cloverleaf
153153.0CO 21 – Powers Boulevard, Interquest ParkwayDiamond
156156.0CO 83 – Baptist Road, MonumentPartial diamond
158158.0CO 105 – Palmer Lake, MonumentDiamond
161161.0CO 105 – MonumentPartial cloverleaf
163163.0County Line Road – Black ForestDiamond
167167.0CO 86 – Dakan RoadPartial diamond
170170.0CO 83 – Black ForestDiamond
172172.0CO 21 – Black Forest RoadPartial diamond
174174.0CO 83 – Shoup RoadDiamond
175175.0CO 86 – GreenlandPartial cloverleaf
178178.0CO 83 – Palmer LakeDiamond
181181.0US 85/CO 83 – Founders Parkway, Castle RockPartial diamond
183183.0US 85 – Castle RockDiamond
184184.0Castle Pines ParkwayPartial diamond
185185.0CO 86 – Castle RockDiamond
188188.0US 85 – SedaliaPartial cloverleaf
191191.0CO 83 – Parker RoadDiamond
194194.0US 85 – Lone TreePartial diamond
195195.0CO 88 – Happy Canyon RoadDiamond
197197.0CO 88 – Highlands RanchPartial diamond
199199.0C-470Cloverleaf
200200.0I-225 – AuroraPartial cloverleaf
201201.0US 285/SH 30 – Hampden AvenueDiamond
202202.0US 85 – Santa Fe DrivePartial diamond
203203.0CO 177 – BroadwayDiamond
204204.0US 285 – Hampden Avenue westPartial diamond
205A205.0US 285 north – Santa Fe Drive (northbound)-
205B205.5US 285 south – Santa Fe Drive (southbound)-
206206.0CO 121 – Wadsworth BoulevardDiamond
207207.0US 36 – Boulder TurnpikePartial cloverleaf
209209.06th AvenueDiamond
210210.0CO 119 – 58th AvenuePartial diamond
211A211.0I-70 east – Limon (northbound)Stack (part of Mousetrap)
211B211.5I-70 west – Denver (southbound)Stack (part of Mousetrap)
212212.023rd/20th AvenuePartial diamond
213213.0CO 26 – Park Avenue WestDiamond
214214.0I-70/I-76 – Airport (Mousetrap)Stack interchange
215A215.020th Street – Downtown DenverPartial diamond
215B215.5CO 3 – Clay Street-
216216.0US 6/US 85 – 6th AvenueDiamond
217217.046th/48th AvenuePartial diamond
218218.0SH 7 – 56th/58th AvenueDiamond
220220.088th AvenuePartial cloverleaf
222222.0104th AvenueDiamond
223223.0120th Avenue – WestminsterPartial diamond
225225.0144th AvenueDiamond
226226.0160th Avenue – ThorntonPartial diamond
228228.0BroomfieldDiamond
229229.0US 36 – BoulderPartial cloverleaf
232232.0104th AvenueDiamond
235235.0CO 7 – LafayettePartial diamond
240240.0US 287 – Fort CollinsTrumpet
243243.0CO 14 – Fort CollinsDiamond
250250.0CO 60 – MillikenPartial diamond
255255.0US 34 – LovelandCloverleaf
257257.0CO 402 – LovelandDiamond
262262.0CO 1 – BerthoudPartial diamond
267267.0CO 56 – BerthoudDiamond
270270.0CO 66 – LongmontPartial cloverleaf
275275.0CO 119 – LongmontDiamond
280280.0US 287 – LongmontPartial diamond
285285.0CO 66 – PlattevilleDiamond
290290.0CO 14 – AultPartial diamond
295295.0County Road 74 – PierceDiamond
299299.00Wyoming state line-

Wyoming

Interstate 25 enters at milepost 0 from the state line south of and extends 300.53 miles north to its junction with Interstate 90 in , featuring approximately 50 exits that connect to local highways, business routes, and energy-related infrastructure in the . The route supports lower average daily traffic volumes of 40,000 to 80,000 vehicles compared to urban segments in , reflecting its rural character, with partial cloverleaf or diamond interchanges in remote areas providing limited access to former U.S. Route 87 alignments and ranch roads. Weigh stations near Casper at mileposts 188 and 189 monitor heavy traffic from and transport corridors. In Wyoming, I-25 follows the Front Range from northward through Wheatland and Douglas, entering the near Casper. It passes Glendo State Park and rural energy areas before reaching , where it meets I-90, providing access to the and eastern plains. Key connections include Exit 7 to Interstate 80 west of for regional freight, Exit 96 to Wyoming Highway 59 north toward Douglas and Gillette's energy fields, Exit 194 serving Casper's industrial areas via local roads, and the northern terminus at Exit 301 linking to Interstate 90 for access to the . These exits facilitate movement along the historic - stagecoach route, now overlaid by I-25, with notes on services like fuel and lodging concentrated near urban centers such as , Wheatland, Casper, and .
ExitMilepostDestinationsNotes
-0.000Colorado State LineSouthern terminus in Wyoming; Laramie County. Former US 85 alignment.
22.3WY 223 – Terry Ranch RoadPartial access; rural ranch road east of Cheyenne.
44.1High Plains RoadLocal access near Cheyenne; no major services.
77.2I-80 / US 30 – College Drive / I-25 Bus.Major interchange for Cheyenne; west to Laramie, east to Sidney, NE. Fuel, food, lodging.
99.0US 30 West – LincolnwayAccess to downtown Cheyenne; commercial district.
1010.4Missile DriveMilitary and industrial access near F.E. Warren AFB.
1111.2Randall Avenue / Pershing BoulevardResidential and commercial in Cheyenne. Pharmacies, shopping.
1212.1Central Avenue / I-25 Bus. / US 85 SouthPartial interchange; connects to historic US 85. Fuel, food.
1313.0Vandehei AvenueNorthern Cheyenne access; shopping, pets services.
1616.3WY 211 – Horse Creek RoadRural exit west to Horse Creek; limited services.
1717.1US 85 North – TorringtonCloverleaf; north to Fort Laramie historic site.
2121.4Ridley RoadAgricultural access; no services detected.
2525.0Unmarked (local road)Partial access near Pine Bluffs; former alignment.
2929.5Whitaker RoadRural; connects to WY 215 east.
3434.4Nimmo RoadLocal ranch road; no services.
3939.2Little Bear RoadPartial interchange; Bear Creek area.
4747.0Bear Creek Road / Laramie CR 245Platte County line nearby; rural.
5454.0I-25 Bus. – ChugwaterBusiness loop access; food available.
5757.3I-25 Bus. (16th Street)Chugwater services; former US 87.
6565.1Slater RoadRural partial access.
6666.0Hunton RoadNear Wheatland; agricultural.
6868.2Antelope RoadLocal road; no services.
7070.4Bordeaux RoadAccess to Laramie River; partial.
7373.1WY 34 West – Laramie / WheatlandWest to Guernsey Reservoir; fuel.
7878.0I-25 Bus. / US 87 Bus. – 16th StreetWheatland business district; lodging.
8080.2US 87 North – WheatlandCommercial access; food, shopping.
8484.0West Laramie River RoadRural; river access.
9292.3US 26 East – Guernsey / TorringtonEast to Fort Laramie; partial interchange.
9494.1El Rancho RoadLocal; no services.
9696.0WY 59 – Douglas / GilletteMajor energy corridor north; fuel, truck services. Coal and oil transport.
100100.2Cassa RoadNear Glendo Reservoir; recreational.
104104.0Glendo State ParkEast to park; camping, outdoors.
111111.3GlendoLocal access; food.
126126.0US 18 / US 20 East – LuskEast to Nebraska; diamond interchange.
135135.2I-25 Bus. – DouglasBusiness loop; Douglas services.
140140.0WY 59 – Douglas / GilletteSouth end of WY 59; energy hub. Truck parking.
146146.1WY 96 – DouglasLocal highway east.
151151.0Ayres Natural BridgeWest to park; recreational access.
165165.3Glenrock / Rolling HillsGlenrock access; fuel, food.
172172.0Salt Creek RoadRural; Converse County.
182182.0Hat Six Road / Brooks RoadNorth to Evansville; partial. Weigh station nearby.
185185.0Wyoming Boulevard – EvansvilleSouth Casper; commercial.
186186.2I-25 Bus. / US 20 / US 26 / US 87 Bus. – Beverly StreetCasper loop south; major services. Fuel, medical.
187187.0McKinley StreetDowntown Casper access.
188A188.1Center StreetCasper central; shopping.
188B188.5WY 220 West – Poplar Street / Port of EntryWeigh station; west to Alcova. Truck inspection.
189189.0US 20 / US 26 West – ShoshoniPartial; westbound port of entry.
191191.6Wardwell RoadIndustrial near Casper; energy facilities.
194194.0I-25 Bus. – CasperBusiness route to east Casper.
197197.2Ormsby RoadRural north of Casper.
210210.0WY 259 – Horse Ranch Creek RoadLocal access; no services.
216216.3Alcova RoadNear Alcova Lake; recreational.
227227.0WY 387 – Midwest / EdgertonEast to oil fields; truck route.
235235.0Tisdale Mountain Road / WY 196Rural; partial access.
246246.2Unmarked (local)Near Kaycee; no services.
249249.0WY 196 – KayceeTown access; fuel.
254254.1KayceeMain street; food, lodging.
265265.0Reno RoadRural partial; ranch access.
291291.3Trabing RoadNear Buffalo; local.
298298.0I-25 Bus. / US 87 Bus. – BuffaloBusiness loop; downtown access. Lodging.
299299.2US 16 – BuffaloEast to Tensleep; commercial.
301301.0I-90 – BuffaloNorthern terminus; east to Sheridan, west to Gillette. Major junction for energy and tourism.

History

Planning and designation

The planning and designation of Interstate 25 (I-25) emerged as part of the national established by the , which authorized the construction of approximately 41,000 miles of controlled-access highways to connect major population centers, borders, and ports across the . This legislation, signed by President on June 29, 1956, envisioned a network that would facilitate interstate commerce, national defense, and rapid travel, with federal funding covering 90 percent of costs. I-25 was identified as a key north-south corridor in the western , linking the region near the Mexican border at , to the northern plains at , thereby supporting economic ties between the Southwest and the . The route numbering for the Interstate system was finalized in 1957 by the Bureau of Public Roads (BPR, predecessor to the ) and the American Association of State Highway Officials (AASHO), following principles where odd numbers denoted north-south routes and even numbers east-west routes, with numbers generally increasing eastward for north-south highways and northward for east-west ones. I-25 received its designation on August 14, 1957, as the third primary north-south route from the , positioned as a western parallel to the more central I-35 and reflecting the system's grid-like logic to ensure logical connectivity. This numbering aligned with the route's role in serving the Rocky Mountain front range, from the international border vicinity to the prairies. The highway earned the nickname "Pan-American Freeway" early in its conceptualization, inspired by visions of integrating it with the broader network to promote hemispheric trade and travel from northward. Initial route planning for I-25 closely followed the established corridor of U.S. Route 85 (US 85), a pre-existing north-south highway that had been developed since the 1920s along the eastern edge of the Rocky Mountains, providing a logical alignment from Las Cruces northward through Albuquerque, Colorado Springs, Denver, and Cheyenne to the Wyoming state line, with extensions over Raton Pass and beyond into Wyoming. The full route, spanning about 1,062 miles across New Mexico, Colorado, and Wyoming, received federal approval in 1957 as part of the phased designation of the Interstate system, building on preliminary mappings from the 1940s that prioritized connections to border areas and resource-rich regions. Design standards mandated a minimum of four 12-foot lanes in a divided configuration, full control of access via interchanges, and geometric features supporting speeds up to 70 mph, with specific provisions for heavy truck traffic—including climbing lanes on grades—and adaptations for mountainous terrain such as wider shoulders and reinforced structures to handle snow, ice, and steep inclines. Early planning faced notable engineering controversies, particularly at on the Colorado-New Mexico border, where the existing US 85 involved steep grades exceeding 6 percent over a 7,800-foot elevation, challenging the Interstate's uniform high-speed standards and requiring innovative cut-and-fill earthwork, retaining walls, and drainage systems to mitigate landslides and avalanches in the rugged . debates also arose near , where proposals to route the freeway through the city's densely populated North Valley sparked concerns over urban disruption, land acquisition from historic acequia-irrigated farmlands, and potential flooding risks from the , leading to revised that balanced connectivity with local impacts during the late 1950s federal-state coordination. These issues highlighted the tensions between national mobility goals and regional topography and community needs in finalizing the route.

Construction phases

Construction of Interstate 25 began in the late 1950s following the , which authorized the and provided for its development across the three states it traverses. The project progressed in phases, with segments built concurrently in multiple locations to connect existing highways like , emphasizing efficient routing through mountainous and desert terrain. By the 1970s, most of the route was operational, though completion extended into the early 1980s due to funding delays and challenging geography. In , initial construction started near Las Cruces in 1957 as part of the early Interstate build-out, linking to I-10 and extending northward through rural areas. A key milestone was the opening of the "Big I" interchange in Albuquerque in 1966, a complex five-level connecting I-25 with I-40 at a cost designed for 40,000 vehicles per day. Progress continued northward, with the final segment over near the Colorado border completed in the mid-1970s, marking full continuity from Las Cruces to the state line. Colorado's portion advanced rapidly after designation, building on the pre-existing Valley Highway in Denver, where construction from 1948 to 1958 provided the foundational urban freeway segment. The link between and was established in the early 1960s, with the Pueblo Freeway interchange completed by 1959 and extensions northward following soon after. The route's southern end connected via a 21-mile segment south of Walsenburg in 1969, finalizing Colorado's 299-mile alignment at a total cost of $125 million. Wyoming's build-out started with segments near Cheyenne in the late 1950s, including a 10.1-mile section awarded in 1956 and opened by 1960, integrating with I-80. Mid-route progress from Casper toward occurred through the 1960s, replacing older alignments with modern freeway standards. The last major gap, a 26.5-mile stretch between Casper and Kaycee, opened on February 2, 1982, delayed by funding constraints and completing the state's 301-mile portion. The entire Interstate 25 project relied heavily on federal funding, covering 90% of costs through the , with states providing the remaining 10% match. Adjusted for , total expenditures exceeded $1 billion across the route, reflecting the scale of earthwork and infrastructure in varied landscapes. Engineering challenges included multiple bridges over the River, such as the mid-1960s Pan American crossing near Albuquerque, which navigated deep valleys with cantilever designs. At , extensive grading along the historic U.S. 85 alignment achieved a 6% maximum grade without tunnels, minimizing costs while ensuring safe passage over the 7,800-foot elevation.

Major expansions

One of the most significant post-construction upgrades to Interstate 25 occurred in the through the Transportation Expansion (T-REX) Project, completed between 2004 and 2006. This $1.67 billion initiative widened 17 miles of I-25 from to Avenue, adding high-occupancy vehicle lanes, reconstructing interchanges, and integrating 19 miles of new service along the Southeast Corridor to address growing and multimodal needs. The project, a pioneering design-build effort, also included environmental mitigations such as wetland restoration and noise barriers to minimize impacts on urban habitats. In Colorado Springs, the Colorado Springs Metro Interstate Expansion (COSMIX) project from 2006 to 2007 focused on widening I-25 to three lanes in each direction over a 12-mile stretch south of the city, at a cost of $150 million. This effort rebuilt key interchanges at Santa Fe Avenue, Platte Avenue, and Circle Drive, improving traffic flow and safety amid rapid suburban growth. It incorporated intelligent transportation systems for real-time monitoring and addressed capacity constraints for freight and commuter traffic. More recent Colorado projects include the 2024 update to the South I-25 Corridor Study, which examines needs from C-470 to the Douglas County line, emphasizing multimodal enhancements like , bike/pedestrian facilities, and -focused access in southern Denver suburbs. The study forecasts 20-year growth in employment and housing, recommending integrated transportation solutions to reduce reliance on single-occupancy vehicles while supporting economic vitality. In 2022, the Department of Transportation halted plans to widen I-25 north of from US 36 to SH 119 due to environmental concerns, including disruption, and issues disproportionately affecting low-income communities, shifting focus to managed lanes and alternatives. As of 2025, ongoing safety and operations improvements along I-25, including the South Gap segment from to Castle Rock, involve environmental assessments for barrier replacements, pavement resurfacing, and interchange upgrades to enhance crash reduction in this high-speed corridor. In , widening efforts near Albuquerque in the targeted congestion hotspots, such as the reconstruction of the I-25/I-40 "Big I" interchange extensions and auxiliary lanes added between Paseo del Norte and Jefferson Street to accommodate urban freight and commuter volumes. The ongoing I-25 Improved project, launched in 2024 and projected to complete by 2027, represents a $268 million reconstruction from Comanche Road to Montgomery Boulevard, including full-depth pavement replacement, bridge widenings, and safety features like rumble strips and lighting to cut accident rates by up to 30%. The NM 500 Rio Bravo Bridge Replacement project, initiated in planning stages in 2023, began construction in late 2025 to address structural deficiencies and flood risks over the , with the new spans expected to provide enhanced seismic resilience and scour protection upon completion in 2029. Wyoming's expansions from 2015 to 2020 in the Casper area prioritized freight efficiency, including pavement rehabilitation and auxiliary lane additions along I-25's marginal roads to support energy sector haulage amid increasing truck traffic. In , 2023 saw the Wyoming Department of Transportation (WYDOT) receive a $13 million federal grant to fund the final design work for a new configuration at the I-25/I-80 interchange, aimed at improving merge safety and accommodating projected volume growth.

Exit list

New Mexico

Interstate 25 in spans approximately 462 miles from its southern terminus at in Las Cruces to the state line north of Raton, with exits numbered sequentially from 0 to 460 based on mileposts. The following table lists all exits along I-25 in , compiled from northbound configurations (which generally apply bidirectionally unless noted), including exit numbers, approximate mile markers where available, primary destinations served, and brief notes on significance such as services, restrictions, or traffic volume.
ExitMileDestinations (Northbound/Southbound)Notes
00I-10 E/W – Las Cruces, Deming, El Paso TXSouthern terminus; major interstate junction.
11NM 292 – University Ave, Las CrucesAccess to ; key local entry.
33Lohman Ave – Las CrucesCommercial area with fuel and food services.
66US 70 E – Alamogordo, Del Rey BlvdEastward connection to .
99NM 320 – Dona AnaRural access; limited services.
1919Radium SpringsScenic area near ; rest area nearby.
3232County Road E071 – RinconTruck turnout available.
3535NM 140 – Hatch, RinconAgricultural region; US Border Patrol checkpoint.
4141NM 26 W – HatchLocal town access.
5151NM 546 – Garfield, SalemRural farming area.
5959NM 187 – Caballo, Percha State ParksAccess to Elephant Butte Lake recreation.
6363NM 152 – HillsboroConnection to historic sites.
7171Las PalomasLimited rural access.
7575Williamsburg, loop entry.
7979I-25 BUS – Town center; US Border Patrol checkpoint.
8383Elephant Butte Lake State ParkMajor recreation area.
8989Martin Ranch Rd – Local ranch access.
9292Mitchell PointScenic overlook.
100100Red RockState park access.
115115NM 107 – San Antonio, Camino Real International Heritage CenterHistoric trail site; at mile 114.
124124NM 178 – Willow Springs Ranch RdRural.
139139US 380 E – San Antonio, CarrizozoEast-west connector.
147147US 60 W – Socorro, MagdalenaMajor east-west route.
150150US 60 W, I-25 BUS W – Socorro loop.
152152EscondidaLocal access.
156156NM 408 – LemitarRural.
163163San Acacia.
175175US 60 E – Bernardo, MountainairEastward to Salinas Pueblo Missions.
190190I-25 BUS – South access.
191191Camino Del Llano – Local.
195195Main town entry.
203203NM 6 – Los LunasConnection to historic Route 66.
209209NM 317, NM 314, NM 45 – Isleta lands; high ADT approaching Albuquerque.
213213NM 314 – Isleta Blvd access.
215215NM 47 – Albuquerque crossing; ADT exceeds 150,000 vehicles daily in urban core.
220220NM 500 – Rio Bravo BlvdSouth Albuquerque industrial.
221221Sunport Blvd – Major ; ADT around 204,000 in metro area.
222222Gibson Blvd – Kirtland AFBMilitary base; HOV lane evaluations in corridor.
223223Avenida – AlbuquerqueUniversity district.
224224Coal Ave, Lead Ave, Central Ave – Albuquerque access; high urban traffic.
225225Lomas Blvd, Menaul Blvd, Candelaria Rd – AlbuquerqueCentral city; ADT peaks at 204,000.
226226I-40 E/W – AlbuquerqueMajor junction with transcontinental interstate; Big I interchange.
227227Comanche Rd, Griegos Rd – AlbuquerqueNorth valley.
228228Montgomery Blvd, Montano Rd – AlbuquerqueCommercial corridor.
229229Jefferson St – AlbuquerqueLocal.
230230San Mateo Blvd, Osuna Rd – AlbuquerqueShopping areas.
231231Pan American Frontage Rd NB access.
232232NM 423 – Paseo del Norte – AlbuquerqueNorthern suburbs.
233233Alameda Blvd, NM 528 – Albuquerque access.
234234NM 556, Tramway Rd, Roy Ave – AlbuquerqueFoothills entry.
240240NM 473 – BernalilloTown center.
242242NM 165 E, US 550 W – Placitas, Bernalillo access.
248248NM 315 – AlgodonesLocal.
252252San Felipe Tribal lands.
257257Budaghers.
259259NM 22 – Santo Domingo access.
264264NM 16 – Cochiti Historic sites.
267267Waldo, Canyon Rd – Southern approach to .
271271La Cienega, NM 50Local.
276276NM 599 S – bypass.
278278NM 14 S/N – , Cerrillos Rd – Turquoise Trail; city entry.
282A/B282US 84 N, US 285 N – St. Francis Dr, Northern terminus of concurrency; tourist hub.
284284NM 466 – Old Pecos Trail – Historic route.
290290US 285 S – Clines CornersSouthward to I-40.
294294Sleeping RdRural.
299299NM 50 – Glorieta, Pecos historic battle site.
307307NM 63, NM 50 – Rowe, PecosLocal towns.
319319San Juan, San JoseRural.
323323NM 3 S – VillanuevaScenic byway.
330330BernalLocal.
339339US 84 S – Romeroville, Santa RosaWest to I-40.
343343NM 283, I-25 BUS, NM 329 – Town entry.
345345NM 65, NM 104 – , University Ave access.
347347I-25 , NM 250 – loop.
352352Municipal .
356356Onava – Local.
361361Local roadRural; unnamed exit.
364364NM 161, NM 97 – Valmora, WatrousLocal.
366366NM 161, NM 97 – Watrous, ValmoraDuplicate access.
387387NM 120 – Wagon MoundEast-west connector.
393393LevyRural.
404404NM 569 – Colmor, Local.
412412I-25 Town loop.
414414Main entry.
419419NM 58 W – access.
426426NM 505 – .
435435Tinaja – RatonRural.
446446US 64 W – TaosConnection to .
450450I-25 – RatonSouth Raton.
451451US 64 E, US 87 E – Clayton, RatonEastern plains; truck port of entry nearby at mile 460.
452452NM 72 E – Folsom, RatonCapulin Volcano access.
454454I-25 BUS, 2nd St – RatonDowntown Raton.
460460Colorado State LineNorthern terminus; Raton Pass elevation 7,834 ft; seasonal truck chain requirements possible.
Note: Destinations are primarily northbound but serve both directions; minor variations may exist for southbound ramps. HOV lanes are under evaluation in the Albuquerque corridor but not dedicated permanent facilities. Truck restrictions include inspections at Raton and potential winter chain laws in . Average daily traffic (ADT) in the Albuquerque area reaches up to 204,000 vehicles, establishing it as the busiest segment.

Colorado

Interstate 25 in features about 100 exits over its 298.6-mile length, from mile 0 at the state line near Trinidad to mile 299 at the state line north of Fort Collins. The interchanges vary significantly, with rural sections south of and north of Fort Collins exhibiting longer gaps between exits—often 10-20 miles—characterized by simple or partial cloverleaf designs to accommodate lower volumes and mountainous . In contrast, the urban corridor from to Fort Collins includes denser clustering of exits, with complex multi-level stack interchanges in major cities like and Colorado Springs to handle high congestion; average daily traffic (ADT) reaches peaks exceeding 250,000 vehicles in the metro area, necessitating innovations like managed express lanes and advanced interchange geometries. As of November 2025, ongoing construction at the I-25/US 50 Business interchange (exit 100) in includes bridge replacements and a planned (DDI), with southbound ramps closed until expected completion in summer 2027; detours use CO 47 (exit 110) and CO 96. Key highlights among these exits include Exit 2 near Trinidad, a serving CO 12 and local access to the historic town; Exit 101, the infamous —a five-level with I-70 in , rebuilt multiple times for seismic resilience and traffic efficiency following a 1984 structural incident; Exit 147 in Colorado Springs, a partial cloverleaf with US 24 (Cimarron Street) providing access to downtown and military installations; and Exit 240 in Fort Collins, a trumpet-style interchange with US 287 (College Avenue), facilitating connectivity to and northern rural areas. Special notes on modern enhancements include diverging diamond interchanges (DDIs) introduced in the 2010s to reduce conflict points and delay, such as the one at exit 144 (Fillmore Street) in Colorado Springs (opened 2016); a DDI is under construction at the surface intersection of CO 21 (Powers Boulevard) and Airport Road near exit 150, expected completion in late 2026. Additionally, reversible express lanes operate between Exits 207 (US 36) and 216 (), dynamically pricing tolls to optimize flow on segments with ADT over 200,000. The T-REX project in the early 2000s affected several Denver-area exits like 200 (I-225) by integrating , while terrain influences spacing, with fewer exits in the hilly region compared to the flat plains north of . The following table enumerates all exits, including number, approximate milepost, primary destinations/locations, and interchange type where documented (based on CDOT design standards favoring diamonds in rural areas and more complex forms urbanely).
ExitMileLocationsType
-0.00New Mexico state line (near Raton Pass)-
10.5County Road GG.5 – StarkvilleDiamond
22.0CO 12 – Trinidad, CokedaleDiamond
33.5CO 12 – Trinidad (northbound)Partial diamond
44.0Washington Street – TrinidadDiamond
55.5CO 71 – Starkville, AguilarDiamond
1111.0CO 10 – Ludlow, Trinidad State ParkDiamond
1212.0County Road 31.5 – LudlowPartial diamond
1515.0County Road 41.5 – GulnareDiamond
2020.0US 350 – Starkville, WestonDiamond
2525.0County Road 61.5 – TercioPartial diamond
2727.0CO 12 – Hoehne, MadridDiamond
3232.0County Road 70.8 – RinconDiamond
3737.0County Road FF – Aguilar vicinityPartial diamond
4242.0CO 69 – AguilarDiamond
4747.0County Road 41 – WalsenburgDiamond
5252.0I-25 Frontage Road – WalsenburgPartial diamond
5656.0CO 69 – Walsenburg, GardnerDiamond
5959.0US 160 – Walsenburg, Fort GarlandCloverleaf
6262.0County Road EE.5 – Gardner vicinityDiamond
6868.0CO 10 – La Veta, WalsenburgPartial diamond
7272.0County Road 520 – South Spanish Peak areaDiamond
7878.0US 160 – Fort Garland, AlamosaDiamond
8282.0County Road 21 – San Isabel National ForestPartial diamond
9090.0CO 69 – Rye, WetmoreDiamond
9494.0Pueblo BoulevardPartial cloverleaf
9696.0US 50 Bus. – PuebloDiamond
9898.0CO 45 – Pueblo BoulevardPartial diamond
100100.0US 50 – Pueblo (DDI under construction, expected 2027)Diamond (planned DDI)
101101.0I-25 north to US 50 east-
102102.0US 50 Bus. – Pueblo (Abilene Road)Diamond
104104.0CO 96 – PuebloCloverleaf
108108.0US 85 Bus. – Pueblo (Santa Fe Avenue)Partial diamond
110110.0CO 47 – Pueblo Memorial AirportDiamond
114114.0US 85/87 – PuebloPartial cloverleaf
116116.0CO 45 – Pueblo WestDiamond
118118.0US 85/87 – PenrosePartial diamond
123123.0CO 115 – Florence, PenroseDiamond
125125.0County Road 300 – FlorencePartial diamond
129129.0CO 120 – FlorenceDiamond
131131.0CO 21 – FountainDiamond
135135.0CO 85 – Security-WidefieldPartial diamond
138138.0CO 16 – StratmoorDiamond
140140.0CO 85 – Fort CarsonPartial cloverleaf
142142.0CO 85 – Lake Avenue, Colorado SpringsDiamond
144144.0US 24 Bus. – Colorado SpringsPartial diamond
145145.0CO 85 – Academy BoulevardDiamond
146146.0CO 85 – Platte AvenuePartial diamond
147147.0US 24 – Cimarron Street, Colorado SpringsPartial cloverleaf
148148.0CO 85 – Nevada AvenueDiamond
149149.0CO 85 – Tejon StreetPartial diamond
150150.0CO 21 – Powers BoulevardDiamond
151151.0CO 85 – Union BoulevardDiamond
152152.0Woodmen RoadPartial cloverleaf
153153.0CO 21 – North Academy BoulevardDiamond
156156.0CO 83 – Baptist Road, MonumentPartial diamond
158158.0CO 105 – Palmer Lake, MonumentDiamond
161161.0CO 105 – MonumentPartial cloverleaf
163163.0County Line Road – Black ForestDiamond
167167.0CO 86 – Dakan RoadPartial diamond
170170.0CO 83 – Black ForestDiamond
172172.0CO 21 – Black Forest RoadPartial diamond
174174.0CO 83 – Shoup RoadDiamond
175175.0CO 86 – GreenlandPartial cloverleaf
178178.0CO 83 – Palmer LakeDiamond
181181.0US 85/CO 83 – Founders Parkway, Castle RockPartial diamond
183183.0US 85 – Castle RockDiamond
184184.0Castle Pines ParkwayPartial diamond
185185.0CO 86 – Castle RockDiamond
188188.0US 85 – SedaliaPartial cloverleaf
191191.0CO 83 – Parker RoadDiamond
194194.0US 85 – Lone TreePartial diamond
195195.0CO 88 – Happy Canyon RoadDiamond
197197.0CO 88 – Highlands RanchPartial diamond
199199.0C-470Cloverleaf
200200.0I-225 – AuroraPartial cloverleaf
201201.0US 285/SH 30 – Hampden AvenueDiamond
202202.0US 85 – Santa Fe DrivePartial diamond
203203.0CO 177 – BroadwayDiamond
204204.0US 285 – Hampden Avenue westPartial diamond
205A205.0US 285 north – Santa Fe Drive (northbound)-
205B205.5US 285 south – Santa Fe Drive (southbound)-
206206.0CO 121 – Wadsworth BoulevardDiamond
207207.0US 36 – Boulder TurnpikePartial cloverleaf
209209.06th AvenueDiamond
210210.0CO 119 – 58th AvenuePartial diamond
211A211.0I-70 east – Limon (northbound)Stack (part of Mousetrap)
211B211.5I-70 west – Denver (southbound)Stack (part of Mousetrap)
212212.023rd/20th AvenuePartial diamond
213213.0CO 26 – Park Avenue WestDiamond
214214.0I-70/I-76 – Airport (Mousetrap)Stack interchange
215A215.020th Street – Downtown DenverPartial diamond
215B215.5CO 3 – Clay Street-
216216.0US 6/US 85 – 6th AvenueDiamond
217217.046th/48th AvenuePartial diamond
218218.0SH 7 – 56th/58th AvenueDiamond
220220.088th AvenuePartial cloverleaf
222222.0104th AvenueDiamond
223223.0120th Avenue – WestminsterPartial diamond
225225.0144th AvenueDiamond
226226.0160th Avenue – ThorntonPartial diamond
228228.0BroomfieldDiamond
229229.0US 36 – BoulderPartial cloverleaf
232232.0104th AvenueDiamond
235235.0CO 7 – LafayettePartial diamond
240240.0US 287 – Fort CollinsTrumpet
243243.0CO 14 – Fort CollinsDiamond
250250.0CO 60 – MillikenPartial diamond
255255.0US 34 – LovelandCloverleaf
257257.0CO 402 – LovelandDiamond
262262.0CO 1 – BerthoudPartial diamond
267267.0CO 56 – BerthoudDiamond
270270.0CO 66 – LongmontPartial cloverleaf
275275.0CO 119 – LongmontDiamond
280280.0US 287 – LongmontPartial diamond
285285.0CO 66 – PlattevilleDiamond
290290.0CO 14 – AultPartial diamond
295295.0County Road 74 – PierceDiamond
299299.00Wyoming state line-

Wyoming

Interstate 25 enters at milepost 0 from the state line south of and extends 300.25 miles north to its junction with Interstate 90 in , featuring approximately 50 exits that connect to local highways, business routes, and energy-related infrastructure in the . The route supports lower average daily traffic volumes of 40,000 to 80,000 vehicles compared to urban segments in , reflecting its rural character, with partial cloverleaf or diamond interchanges in remote areas providing limited access to former U.S. Route 87 alignments and ranch roads. Weigh stations near Casper at mileposts 188 and 189 monitor heavy truck traffic from oil and transport corridors. Key connections include Exit 7 to Interstate 80 west of for regional freight, Exit 96 to Wyoming Highway 59 north toward Douglas and Gillette's energy fields, Exit 194 serving Casper's industrial areas via local roads, and the northern terminus at Exit 301 linking to Interstate 90 for access to the . These exits facilitate movement along the historic Cheyenne-Buffalo stagecoach route, now overlaid by I-25, with notes on services like fuel and lodging concentrated near urban centers such as , Wheatland, Casper, and .
ExitMilepostDestinationsNotes
-0.000Colorado State LineSouthern terminus in Wyoming; Laramie County. Former US 85 alignment.
22.3WY 223 – Terry Ranch RoadPartial access; rural ranch road east of Cheyenne.
44.1High Plains RoadLocal access near Cheyenne; no major services.
77.2I-80 / US 30 – College Drive / I-25 Bus.Major interchange for Cheyenne; west to Laramie, east to Sidney, NE. Fuel, food, lodging.
99.0US 30 West – LincolnwayAccess to downtown Cheyenne; commercial district.
1010.4Missile DriveMilitary and industrial access near F.E. Warren AFB.
1111.2Randall Avenue / Pershing BoulevardResidential and commercial in Cheyenne. Pharmacies, shopping.
1212.1Central Avenue / I-25 Bus. / US 85 SouthPartial interchange; connects to historic US 85. Fuel, food.
1313.0Vandehei AvenueNorthern Cheyenne access; shopping, pets services.
1616.3WY 211 – Horse Creek RoadRural exit west to Horse Creek; limited services.
1717.1US 85 North – TorringtonCloverleaf; north to Fort Laramie historic site.
2121.4Ridley RoadAgricultural access; no services detected.
2525.0Unmarked (local road)Partial access near Pine Bluffs; former alignment.
2929.5Whitaker RoadRural; connects to WY 215 east.
3434.4Nimmo RoadLocal ranch road; no services.
3939.2Little Bear RoadPartial interchange; Bear Creek area.
4747.0Bear Creek Road / Laramie CR 245Platte County line nearby; rural.
5454.0I-25 Bus. – ChugwaterBusiness loop access; food available.
5757.3I-25 Bus. (16th Street)Chugwater services; former US 87.
6565.1Slater RoadRural partial access.
6666.0Hunton RoadNear Wheatland; agricultural.
6868.2Antelope RoadLocal road; no services.
7070.4Bordeaux RoadAccess to Laramie River; partial.
7373.1WY 34 West – Laramie / WheatlandWest to Guernsey Reservoir; fuel.
7878.0I-25 Bus. / US 87 Bus. – 16th StreetWheatland business district; lodging.
8080.2US 87 North – WheatlandCommercial access; food, shopping.
8484.0West Laramie River RoadRural; river access.
9292.3US 26 East – Guernsey / TorringtonEast to Fort Laramie; partial interchange.
9494.1El Rancho RoadLocal; no services.
9696.0WY 59 – Douglas / GilletteMajor energy corridor north; fuel, truck services. Coal and oil transport.
100100.2Cassa RoadNear Glendo Reservoir; recreational.
104104.0Glendo State ParkEast to park; camping, outdoors.
111111.3GlendoLocal access; food.
126126.0US 18 / US 20 East – LuskEast to Nebraska; diamond interchange.
135135.2I-25 Bus. – DouglasBusiness loop; Douglas services.
140140.0WY 59 – Douglas / GilletteSouth end of WY 59; energy hub. Truck parking.
146146.1WY 96 – DouglasLocal highway east.
151151.0Ayres Natural BridgeWest to park; recreational access.
165165.3Glenrock / Rolling HillsGlenrock access; fuel, food.
172172.0Salt Creek RoadRural; Converse County.
182182.0Hat Six Road / Brooks RoadNorth to Evansville; partial. Weigh station nearby.
185185.0Wyoming Boulevard – EvansvilleSouth Casper; commercial.
186186.2I-25 Bus. / US 20 / US 26 / US 87 Bus. – Beverly StreetCasper loop south; major services. Fuel, medical.
187187.0McKinley StreetDowntown Casper access.
188A188.1Center StreetCasper central; shopping.
188B188.5WY 220 West – Poplar Street / Port of EntryWeigh station; west to Alcova. Truck inspection.
189189.0US 20 / US 26 West – ShoshoniPartial; westbound port of entry.
191191.6Wardwell RoadIndustrial near Casper; energy facilities.
194194.0I-25 Bus. – CasperBusiness route to east Casper.
197197.2Ormsby RoadRural north of Casper.
210210.0WY 259 – Horse Ranch Creek RoadLocal access; no services.
216216.3Alcova RoadNear Alcova Lake; recreational.
227227.0WY 387 – Midwest / EdgertonEast to oil fields; truck route.
235235.0Tisdale Mountain Road / WY 196Rural; partial access.
246246.2Unmarked (local)Near Kaycee; no services.
249249.0WY 196 – KayceeTown access; fuel.
254254.1KayceeMain street; food, lodging.
265265.0Reno RoadRural partial; ranch access.
291291.3Trabing RoadNear Buffalo; local.
298298.0I-25 Bus. / US 87 Bus. – BuffaloBusiness loop; downtown access. Lodging.
299299.2US 16 – BuffaloEast to Tensleep; commercial.
301301.0I-90 – BuffaloNorthern terminus; east to Sheridan, west to Gillette. Major junction for energy and tourism.

Auxiliary and business routes

Auxiliary routes

Interstate 25 has one official auxiliary route: Interstate 225 in . Interstate 180 in is officially an auxiliary of Interstate 80 but serves as a critical urban link for I-25 traffic entering the capital region. These spurs provide urban connections and relief from mainline congestion, adhering to such as full , , and minimum design speeds where feasible, though I-180 includes at-grade intersections due to its urban nature. No auxiliary routes serve I-25 in , though early planning in the considered loops around Albuquerque to bypass city traffic, such as proposed beltway concepts that were ultimately not designated as Interstates. Interstate 225 (I-225) is a 12-mile spur in the Denver metropolitan area, branching northeast from I-25 in southeast Denver and terminating at I-70 in Aurora, functioning as an eastern bypass for through traffic avoiding the congested central city. Constructed primarily in the late 1960s and 1970s as an extension of the Valley Highway system, it began with a 1-mile segment opening in June 1966 near I-70, followed by phased expansions that reached full completion on May 21, 1976, with the final 1.2 miles from Yosemite Street to I-25. Designed to alleviate urban congestion in growing suburbs, I-225 handles over 100,000 vehicles per day in its busier sections, supporting commuter flows to Denver International Airport and eastern Colorado corridors. Interstate 180 (I-180) is a short 1.09-mile connector in , linking Interstate 80 (where I-25 terminates) southward along to downtown Cheyenne, providing direct access to the city center from the interstate junction. Construction started in 1977 with widening of existing (Central Avenue) to four lanes, culminating in a full opening on June 1, 1984, after six years of work to upgrade the at-grade arterial to partial Interstate standards for better downtown relief. This route ties into broader urban relief efforts in Cheyenne, facilitating efficient connections despite its brevity and inclusion of traffic signals.

Business routes

Business routes of Interstate 25 serve to connect the freeway with the central business districts of towns and cities it bypasses, preserving access to local commercial areas and historic alignments of U.S. Route 85. These loops typically follow surface streets through downtowns, allowing through traffic to use the faster mainline while directing local and tourist vehicles to services and amenities. Many were established during the freeway's construction phases in the and to mitigate economic impacts on bypassed communities. In , six active business loops exist along I-25, each ranging from about 3 to 7 miles in length and paralleling short bypass segments of the main route. The Williamsburg–Truth or Consequences loop (Business Loop 11) spans 5.71 miles along Broadway Street and through the historic core, recently improved with safety enhancements including new striping and lane configurations completed in 2025. The Socorro loop (Business Loop 12) is 2.88 miles along California Street, concurrent with US 60. Northward, the loop (Business Loop 13) covers 6.65 miles via . The Las Vegas loop (Business Loop 15) is 4.24 miles via Grand Avenue, linking to the historic Plaza. The loop (Business Loop 16) is 3.43 miles along Railroad Avenue. The Raton loop (Business Loop 17) is a 4.16-mile route along Second Street and Canyon Drive, connecting the downtown area to heritage sites. All remain active as of 2025, carrying 10,000 to 50,000 vehicles per average daily traffic (ADT). Colorado hosts two active I-25 business routes, focused on southern communities bypassed by the corridor. The Aguilar business spur (State Highway 25B), roughly 2 miles long, runs via Lynn Road. Walsenburg's business loop (State Highway 25C), approximately 4 miles long, runs along Walsen Avenue and Seventh Street, concurrent with US 160, with resurfacing and safety upgrades ongoing into 2026 to address heavy local use. Earlier business designations in Trinidad, Colorado Springs, and other areas were decommissioned after urban realignments. Traffic volumes on these loops range from 10,000 to 50,000 ADT as of 2025. In Wyoming, seven business loops maintain access to key eastern plains towns along I-25's northern segment. The Cheyenne loop (Wyoming Highway 212 overlap) extends 8 miles via College Drive, Central Avenue, and Warren Avenue, integrating with US 85 Business to reach the state capitol and frontier museums. The Chugwater loop (3.28 miles, WY 321) serves the town center. The Wheatland loop (2.95 miles, US 87 Business) follows South Wheatland Highway. Douglas's route (4.97 miles, concurrent with US 20/26/87 Business) follows Yellowstone Highway and Center Street through the downtown core near the Jackalope statue. The Glenrock loop (6.98 miles, WY 95) follows Deer Creek Road. The Casper loop, approximately 2 miles via Center Street and Bryan Stock Trail, bypasses the city's oil industry hubs and serves the area. Buffalo's loop (1.67 miles, US 87 Business) uses , linking to the Big Horn Mountains gateway. These routes, all active in 2025, see 10,000 to 50,000 ADT and continue to follow pre-freeway US 85 paths. No major decommissions have occurred recently in the state.

References

  1. [1]
    FHWA Route Log and Finder List - Federal Highway Administration
    No information is available for this page. · Learn why
  2. [2]
    [PDF] Transport 2040 Metropolitan Transportation Plan Update
    Interstate 25 begins at the interchange with I-10 in southern Las Cruces and terminates in Montana. The average daily traffic on this facility ranges from. ~ ...
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