Interstate 78
Interstate 78 (I-78) is an east–west Interstate Highway spanning 145.34 miles (233.84 km) across the Northeastern United States, connecting its western terminus at an interchange with Interstate 81 in Union Township, Lebanon County, Pennsylvania—northeast of Harrisburg—to its eastern terminus at Canal Street in Lower Manhattan, New York City, via the Holland Tunnel.[1][2] The route primarily follows a corridor through Pennsylvania (77.50 miles), New Jersey (67.83 miles), and a brief 0.5-mile segment in New York, providing a key nontolled alternative to the Pennsylvania and New Jersey Turnpikes for regional travel.[3][4] In Pennsylvania, I-78 begins at the I-81 interchange and heads eastward through rural and suburban landscapes in Lebanon, Berks, Lehigh, and Northampton counties, intersecting U.S. Route 22 near Allentown and crossing the Lehigh River before reaching the Delaware River at Easton.[3] The highway facilitates significant freight movement, with an average annual daily traffic of over 51,000 vehicles, including substantial truck volumes that support commerce between central Pennsylvania and the New York metropolitan area.[3][5] Entering New Jersey via the I-78 Toll Bridge over the Delaware River, the route continues 67.83 miles eastward, passing through Warren, Hunterdon, Somerset, Union, Essex, and Hudson counties, with connections to major roadways like Interstate 287 and U.S. Route 22.[4] It serves urban centers such as Phillipsburg, Clinton, Somerville, Newark, and Jersey City, where it approaches the Hudson River and enters the Holland Tunnel— a dual-tube underwater crossing operated by the Port Authority of New York and New Jersey that carries I-78 under the river to Manhattan.[4][2] In New York, the designated I-78 segment is limited to the short approach on the Manhattan side, terminating amid the dense infrastructure of Lower Manhattan.[2] Designated as part of the Interstate System in 1957, I-78 was largely completed by the late 1980s, with its development relieving congestion on parallel U.S. highways and enhancing economic ties across the Delaware Valley and New York City regions.[1] Today, it remains a critical artery for over 3.8 million daily vehicle-miles in Pennsylvania alone, underscoring its role in supporting industrial, commercial, and commuter traffic in one of the nation's most densely populated corridors.[3]Overview
Route summary
Interstate 78 (I-78) is an east–west Interstate Highway spanning 146.28 miles (235.41 km) across Pennsylvania, New Jersey, and New York, serving as a key corridor for regional travel and commerce in the northeastern United States.[6] The route begins at its western terminus with an interchange at Interstate 81 (I-81) in Union Township, Lebanon County, Pennsylvania, and extends eastward to its eastern terminus at the entrance plaza of the Holland Tunnel in Manhattan, New York City.[7][2] Designated as part of the National Highway Freight Network, I-78 facilitates the movement of goods by accommodating over 4 million trucks annually, supporting freight transport from inland areas to major ports.[8] In Pennsylvania, the highway covers 77.95 miles (125.50 km), traversing from the I-81 interchange near Fredericksburg across the Delaware River via the I-78 Toll Bridge near Phillipsburg.[9] The New Jersey segment measures 67.83 miles (109.16 km), continuing from the toll bridge in Phillipsburg eastward through the northern part of the state to the Newark Bay–Hudson River waterfront near Jersey City.[4] In New York, I-78 consists of a short 0.50-mile (0.80 km) stub that passes through the Holland Tunnel beneath the Hudson River and terminates at Canal Street in Lower Manhattan.[10] The corridor connects major urban centers such as Allentown in Pennsylvania and Newark in New Jersey, providing an alternative to tolled routes like the Pennsylvania and New Jersey Turnpikes for east–west travel.[6]Significance and traffic
Interstate 78 functions as a vital east-west transportation corridor, linking the industrial Lehigh Valley region in eastern Pennsylvania—home to major manufacturing and distribution hubs—with the densely populated New York City metropolitan area. This connection supports efficient movement of both passengers and goods across the Northeast, bridging rural and suburban areas in central Pennsylvania with urban centers in New Jersey and New York. The route parallels key rail lines like the Raritan Valley Line and integrates with broader interstate systems, handling significant daily traffic.[11] The highway plays a critical role in freight movement, serving as a primary link between Lehigh Valley warehouses and distribution centers and major ports such as Port Newark and Port Elizabeth, which handle substantial container traffic. It accommodates significant volumes of cargo, with key commodities including manufactured products, food, and construction materials, underscoring its importance to the regional supply chain. Truck traffic accounts for 20 to 30 percent of overall volumes, reflecting the corridor's heavy reliance on highway freight to support e-commerce growth and industrial activities in the Lehigh Valley.[12][11] Traffic volumes on Interstate 78 are among the highest in the region, with average annual daily traffic (AADT) exceeding 130,000 vehicles in urban sections near Newark. Truck percentages reach up to 25 percent in high-freight sections, such as those east of Interstate 95, where average daily truck volumes exceed 37,000 as of 2023. These patterns highlight the route's dual role in commuter travel and logistics.[13][12] As a toll-free alternative to Interstate 80 in Pennsylvania, Interstate 78 allows drivers to bypass the Pennsylvania Turnpike's fees while providing access to eastern destinations, appealing to cost-conscious commuters and truckers. In New Jersey, its eastern segment in the Newark area becomes the tolled New Jersey Turnpike Newark Bay-Hudson County Extension from near Interchange 14 to the Holland Tunnel, enabling seamless integration with the tolled system for continued travel toward New York City.[14][15]Route description
Pennsylvania
Interstate 78 begins in Pennsylvania at a trumpet interchange with Interstate 81 in Union Township, Lebanon County, near the community of Lickdale. From this western terminus, the highway proceeds eastward through rural areas of Lebanon and Berks counties, characterized by rolling farmland and forested hills, while bypassing the city of Reading to the south. This initial segment traverses lightly developed landscapes, providing a direct route for through traffic avoiding local urban congestion.[6][7] Near Fredericksburg in Lebanon County, Interstate 78 joins a 43-mile concurrency with U.S. Route 22, forming a major east-west corridor that continues into Lehigh County. Along this overlap, the route expands to six lanes in places to handle increased volume, bypassing Allentown to the south via a 7-mile section (exits 53 to 60) concurrent with PA 309 that skirts the city's southern areas. Here, I-78 crosses the Lehigh River on a multi-span bridge, transitioning into more varied terrain with occasional elevation changes before entering Northampton County near Bethlehem.[7][6] Within Northampton County, the highway maintains its eastward alignment through suburban and semi-rural zones, incorporating truck climbing lanes in hilly sections to facilitate safer passage for commercial vehicles navigating the Appalachian foothills. The route concludes its 77.50-mile length in Pennsylvania at the Delaware River, where it crosses the I-78 Toll Bridge—a four-lane structure managed by the Delaware River Joint Toll Bridge Commission—into Phillipsburg, New Jersey.[7][3][15][16]New Jersey
Interstate 78 enters New Jersey from Pennsylvania across the Delaware River via the I-78 Toll Bridge, a 1,222-foot-long structure connecting Williams Township in Northampton County, Pennsylvania, to Phillipsburg in Warren County, New Jersey.[15] The bridge, opened in 1989, features a one-way toll plaza on the Pennsylvania side with seven lanes for westbound collection and includes a rest area and welcome center nearby.[15] Upon entering New Jersey at milepost 0.00, I-78 proceeds eastward as a freeway through rural portions of Warren and Hunterdon Counties, passing near Clinton where it begins to encounter suburban development.[4] The route then transitions into more developed areas around Somerville in Somerset County, intersecting with major connectors like the Vincent R. Kramer Interchange at I-287 near milepost 29.[4] Continuing east, I-78 traverses the Watchung Mountains through a rock cut in Union and Essex Counties, a significant engineering feature that facilitates passage through the hilly terrain while minimizing environmental impact on nearby reservations.[17] The freeway widens into a local-express lane configuration as it enters the urban core of Essex County, serving Newark with connections to I-95 and the New Jersey Turnpike.[4] In this densely populated region, I-78 assumes the Newark Bay-Hudson County Extension of the New Jersey Turnpike, featuring a toll plaza near milepost 53.16 and the Alexander Hamilton Service Area in Secaucus, Hudson County, which provides amenities for travelers between turnpike interchanges 15E and 16E.[18][19] The route culminates in Hudson County, crossing the Newark Bay Bridge—a toll facility opened in 1956 that spans Newark Bay to Bayonne—before reaching the Holland Tunnel approach at the New York state line near milepost 67.83.[18] This final segment, under the jurisdiction of the New Jersey Turnpike Authority from approximately milepost 58.58 onward, includes another toll plaza near milepost 64.05 and serves as a vital link for trans-Hudson traffic.[4] Overall, I-78 spans 67.83 miles across New Jersey, traversing Warren, Hunterdon, Somerset, Union, Essex, and Hudson Counties from the Delaware River to the Hudson River.[4]New York
Interstate 78 enters New York via the Holland Tunnel, a vehicular crossing under the Hudson River that connects Jersey City, New Jersey, to Lower Manhattan.[2] The tunnel, managed by the Port Authority of New York and New Jersey, emerges in Manhattan at Canal Street, where I-78 briefly continues eastward.[6] This segment serves as the eastern terminus of the interstate, providing direct access to the urban core of New York City. The New York portion of I-78 spans just 0.50 miles and is largely unsigned due to the dense urban environment and space constraints in Manhattan, which preclude standard interstate signage.[6] Upon exiting the tunnel, the route follows a short, unsigned alignment along West Street, cosigned as New York State Route 9A (NY 9A), before reaching its official end at an exit rotary near the intersection with Laight and Canal Streets.[6] This brief stretch integrates I-78 into the local street network, with ramps providing connections to nearby arterials such as Hudson Street, Varick Street, and Beach Street, facilitating primarily local access to Lower Manhattan rather than through-traffic.[6] Originally, plans called for extending I-78 eastward from the Holland Tunnel through Manhattan, Brooklyn, Queens, and into the Bronx to connect with the Bruckner Interchange, where it would meet Interstates 95, 278, 295, and 678.[6] However, these extensions were canceled in the 1970s amid community opposition and shifting urban planning priorities, leaving the current stub as a limited connector focused on regional entry rather than a full crosstown route.[6] Travelers entering New York via I-78 through the Holland Tunnel encounter tolls collected only in the New York-bound direction. As of November 2025, the toll for passenger vehicles with E-ZPass is $16.06 during peak hours (weekdays 6-10 a.m. and 4-8 p.m., weekends 11 a.m.-9 p.m.) and $14.06 off-peak, with the Port Authority overseeing all collections through cashless tolling systems.[20]Major junctions
Key interchanges in Pennsylvania
Interstate 78 in Pennsylvania features 20 numbered exits spanning its 78-mile length from the I-81 interchange to the New Jersey state line, with designs ranging from simple diamond interchanges in rural areas to more complex partial cloverleaf configurations in suburban zones to accommodate higher traffic volumes.[21] The western terminus at Exit 1 connects to Interstate 81 via a directional T interchange at milepost 0 in Union Township, Lebanon County, facilitating seamless access from I-81 north to Hazleton (56 miles) and south to Harrisburg (23 miles) while integrating a partial ramp for local traffic to PA 72 and Lebanon.[6] This design minimizes weaving and supports the route's role as a connector between central Pennsylvania and the Lehigh Valley.[6] A significant concurrency with U.S. Route 22 begins near Fredericksburg in Lebanon County and extends eastward through the Lehigh Valley to the New Jersey state line near Phillipsburg, enhancing connectivity for through traffic from western Pennsylvania to the New York City region via a shared six-lane freeway alignment.[6] In the Allentown vicinity, key interchanges include Exit 60 with PA 309 in South Whitehall Township, a partial cloverleaf design that provides direct southbound access to Quakertown and ties into the Pennsylvania Turnpike (I-476) toll road, handling substantial volumes with an average annual daily traffic (AADT) of approximately 63,459 vehicles on adjacent segments.[6][22] Nearby, Exit 49A at Summit Street in Upper Macungie Township uses a partial cloverleaf interchange to connect to PA 100 south toward Trexlertown, serving industrial parks and local commuters in a suburban setting with controlled acceleration and deceleration lanes.[21][6] Further west, Exit 30 near Hamburg in Berks County stands out as a high-volume diamond interchange, supporting over 44,000 vehicles daily and linking to secondary routes toward Reading while bridging rural and semi-urban traffic flows.[21][22] At the eastern end, Exit 75 integrates the I-78 Toll Bridge crossing into New Jersey, featuring a toll plaza with E-ZPass lanes immediately west of the Delaware River in Williams Township, Northampton County, designed for efficient collection from eastbound traffic heading to Phillipsburg and beyond.[15] This setup, managed by the Delaware River Joint Toll Bridge Commission, includes barrier-separated lanes to handle peak cross-state volumes exceeding 58,000 vehicles per day on nearby segments.[22][15]| Exit Number | Location | Connections | Interchange Type | Notes |
|---|---|---|---|---|
| 1 | Union Township | I-81 (north to Hazleton, south to Harrisburg); TO PA 72 | Directional T | Mile 0; serves as western terminus with partial local ramps.[6] |
| 30 | Hamburg area | Local access to Hamburg (toward Reading) | Diamond | High-volume; AADT ~44,243 on westbound segment.[21][22] |
| 60 | South Whitehall Township | PA 309 (south to Quakertown); TO I-476/PA Turnpike | Partial cloverleaf | Suburban access; AADT ~63,459 east of interchange.[6][22] |
| 49A | Upper Macungie Township | Summit Street; PA 100 (south to Trexlertown) | Partial cloverleaf | Industrial connectivity; part of US 22 overlap initiation.[21][6] |
| 71 | Williams Township | PA 33 (north to Stroudsburg); US 22 east | Diamond | Interchange with PA 33; US 22 concurrency continues to NJ line.[21][6] |
| 75 | Easton area | I-78 Toll Bridge (to NJ); TO PA 611 | Integrated toll plaza | Eastern terminus; E-ZPass compatible for eastbound tolls.[15][21] |