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37th_parallel_north

The 37th parallel north is a circle of latitude 37 degrees north of the Earth's equatorial plane, encircling the globe at an average distance of approximately 4,109 kilometers (2,552 miles) from the equator.^[1] In the United States, this parallel holds particular historical and geographical importance as a boundary line established during 19th-century territorial organization. The Kansas-Nebraska Act of 1854 defined it as the southern border of Kansas Territory (now Kansas) and the northern border of Indian Territory (now Oklahoma).^[2] It also demarcates the southern boundary of Colorado and the northern boundary of New Mexico, as surveyed in the 1860s and confirmed in subsequent Supreme Court rulings.^[3] Further west, it forms the northern border of Arizona and the southern border of Utah, with the Four Corners Monument marking the intersection at the 37th parallel north and 109th meridian west.^[4] These borders facilitated westward expansion and land surveys under the U.S. General Land Office.^[5] Globally, the 37th parallel north traverses diverse regions, including southern Spain near Seville (at approximately 37.4° N), North Africa through Algeria and Tunisia, the Middle East via Turkey, Iran, and Iraq, East Asia across northern China (including cities like Taiyuan at 37.87° N and Yantai at 37° N), Japan, and the western United States through California near Los Angeles (at 34.05° N, but the parallel passes north of the city) and Nevada.^[6]^[7]^[8] The line has been studied for geophysical features, such as gravity and magnetic anomalies across North America, as documented in NASA surveys.^[9] Additionally, it has garnered cultural attention for reported paranormal activity along its U.S. stretch, often termed "America's UFO Highway," with clusters of unexplained sightings and events.^[10]

Geography

Circle of latitude

The 37th parallel north is a circle of latitude, an imaginary east-west line encircling the Earth at 37 degrees north of the equator in the geographic coordinate system. This system divides the planet into parallels of latitude, measured from 0° at the equator to 90° at the poles, with the 37th parallel representing a small circle parallel to the equator. Its radius, the distance from the Earth's axis of rotation, is approximately 5,100 km, resulting in a circumference of about 32,000 km, calculated using the formula for parallel length: equatorial circumference (40,075 km) multiplied by the cosine of the latitude angle.^[11]^[12] Mathematically, the 37th parallel lies within the Northern Hemisphere's temperate zone, positioned 13.5° north of the Tropic of Cancer (23.5°N), which marks the northernmost limit of the tropics, and 29.5° south of the Arctic Circle (66.5°N), beyond which polar day and night occur. This placement influences solar insolation patterns, with the parallel experiencing moderate seasonal variations in sunlight due to Earth's 23.44° axial tilt. The coordinate system's use of latitude allows for precise global positioning, where the 37th parallel serves as a reference for navigation and mapping without crossing the poles.^[13] Along this latitudinal band, climates are predominantly temperate to subtropical, shaped by its position in the mid-latitudes where westerly winds and ocean currents moderate temperatures. Average annual temperatures typically range from 10°C to 18°C, with cooler continental interiors around 10–12°C and warmer coastal areas up to 16–18°C, while precipitation patterns vary from 500–1,000 mm in semi-arid zones to 1,000–1,500 mm in humid regions, often with wet winters and dry summers in western sectors. Ecologically, this fosters diverse vegetation zones, including Mediterranean shrublands with evergreen oaks and chaparral in western coastal areas, transitioning to temperate deciduous forests and grasslands in eastern and central bands, and steppes in inland continental regions.^[14] Daylight duration at the 37th parallel varies seasonally due to Earth's tilt, reaching a maximum of 14 hours and 42 minutes on the summer solstice (around June 21) and a minimum of 9 hours and 37 minutes on the winter solstice (around December 21), assuming civil twilight boundaries. On the summer solstice, the Sun's altitude at solar noon is approximately 76.4°, while on the winter solstice it is about 29.6°, calculated as 90° minus the absolute difference between the latitude and the Sun's declination (±23.44°). These metrics highlight the parallel's balanced exposure to solar energy, supporting moderate ecological productivity.^[15]^[16]

Global path

The 37th parallel north traces an east-west route around the globe at 37 degrees north of the equator, spanning approximately 32,000 kilometers in circumference due to the Earth's curvature. Starting from the Prime Meridian in the Atlantic Ocean, roughly 400 kilometers west of Portugal and north of the Azores archipelago, the parallel enters continental Europe in southern Portugal near Sagres Point. It then crosses central and eastern Spain, passing through the regions of Extremadura, Castile-La Mancha (including the vicinity of Madrid), the Valencian Community, and Aragon, where it encounters the Ebro River and the Sierra Nevada mountain range.^[17]^[1] Continuing eastward, the parallel enters the Mediterranean Sea between Spain and Algeria, then crosses the Algerian coast in the central region before reaching Tunisia on the Cap Bon peninsula. It re-enters the Mediterranean Sea, traversing the Strait of Sicily to cross Italy's island of Sicily and the southern mainland, followed by Greece, including the Peloponnese peninsula and islands such as Sifnos in the Aegean Sea. The route then proceeds through western Turkey in the Adana region, entering northern Syria and northern Iraq, where it crosses the Tigris River north of Baghdad.^[1] Further east, the parallel moves through Iran's central plateau and the Zagros Mountains, then into Turkmenistan across the Karakum Desert, briefly touching Uzbekistan before entering Afghanistan in the Hindu Kush foothills. It then briefly crosses Tajikistan before entering northern Pakistan in the Gilgit-Baltistan region (claimed by India). The route continues into China, traversing from Xinjiang through the Gobi Desert and central provinces to Shandong near Yantai. It then crosses the Yellow Sea to South Korea near the Pyeongtaek area, the Sea of Japan, and Japan in Ishikawa Prefecture. The parallel enters the Pacific Ocean east of Japan, crossing vast expanses before reaching the western coast of the United States in California and continuing eastward through the country to Virginia. It re-enters the Atlantic Ocean off the U.S. East Coast, completing the circle back toward the Prime Meridian. Along its full path, the 37th parallel covers approximately 40% land and 60% water, reflecting a mix of continental interiors, mountain ranges, deserts, rivers, and oceanic segments. Major geographical features include the aforementioned rivers like the Ebro and Tigris, mountain ranges such as the Sierra Nevada and Zagros, the Karakum Desert, and multiple seas and oceans including the Mediterranean, Aegean, Yellow, Sea of Japan, Pacific, and Atlantic.^[17]^[1]

North America

United States

The 37th parallel north enters the contiguous United States from the Pacific Ocean along the central California coast, approximately at the latitude of Bonny Doon near Santa Cruz, crossing coastal plains and farmlands before traversing inland through the San Joaquin Valley toward the Sierra Nevada foothills.^[18] It then proceeds eastward into Nevada, passing through arid Great Basin desert landscapes north of the Las Vegas metropolitan area, roughly 60 miles to the north, and avoiding major urban centers like Reno to the north.^[19] In Nevada, the parallel crosses remote high desert terrain, including areas near Great Basin National Park, before reaching the state's eastern boundary.^[20] Upon entering Utah, the 37th parallel forms the state's entire southern border with Arizona, running from the Nevada tripoint near St. George—a city situated just north of the line in the Virgin River Valley—to the Four Corners Monument, where it meets the borders of Colorado, New Mexico, and Arizona at approximately 37° N, 109° 03' W, though surveys have noted minor discrepancies in the monument's exact placement.^[4]^[21] This segment highlights the parallel's role in the Four Corners region's unique quadripoint configuration, amid red rock plateaus and the edges of the Colorado Plateau. Continuing east, it delineates the southern border of Colorado from the Four Corners to the Kansas state line, passing through the San Luis Valley and near the Sangre de Cristo Mountains, where the terrain shifts from high plains to rugged canyons.^[21] In Kansas, the parallel defines the southern boundary with Oklahoma from the Colorado line near Garden City—located slightly north in the High Plains—to the Missouri border, traversing expansive prairies and agricultural heartlands of the Great Plains, with minimal elevation changes across vast grasslands.^[21] The parallel forms the southern borders of Utah, Colorado, and Kansas, continuing straight east into Missouri, where it crosses the Ozark Mountains near Springfield, featuring rolling hills, karst topography, and forested uplands that mark a transition from the plains.^[22] Further east, the line passes through southern Illinois near Carbondale in the Mississippi River valley, characterized by fertile lowlands and riverine floodplains, before entering Kentucky close to Paducah along the Ohio River.^[23]^[24] The parallel continues through western Kentucky, then enters Virginia near the Kentucky-Virginia border, passing through central Virginia amid the Appalachian foothills with increasing elevation and dense hardwood forests. It ultimately reaches the Chesapeake Bay near Hampton Roads in southeastern Virginia, approaching the Atlantic Ocean amid coastal plains and wetlands.^[25]^[26] Throughout its traverse, the 37th parallel demarcates southern boundaries for Utah, Colorado, and Kansas, as established by 19th-century congressional enabling acts, including its origin in the 1854 Kansas-Nebraska Act that organized territories north of this line.^[21] This path showcases dramatic topographical diversity, from California's Pacific coastal plains and Nevada's basins to the Rocky Mountain peripheries in Colorado and Utah, the open Great Plains of Kansas, and the humid river valleys and Appalachian highlands farther east.^[27]

Mexico and Central America

The 37th parallel north does not cross into Mexico or Central America, as its trajectory through North America remains entirely within the United States, forming the southern boundaries of Utah and Colorado and the northern boundaries of Arizona, New Mexico, and Oklahoma. Northern Mexico, including the states of Chihuahua and Sonora, lies immediately south of Arizona and New Mexico but at latitudes ranging from approximately 29°N to 32°N, placing it several hundred kilometers south of the parallel. Baja California, the peninsula state of Mexico, extends even farther south, with its northern tip near Tijuana at about 32.5°N. Geologically, the region along the 37th parallel in the United States is situated on the North American Plate, a major tectonic unit that encompasses the entirety of Mexico and extends into Central America as far south as central Costa Rica, where it meets the boundary with the Caribbean Plate. This plate's continuity facilitates the extension of structural features from the parallel southward, notably the Basin and Range Province, which continues into northern Mexico as a zone of mid- to late Cenozoic crustal extension characterized by elongate fault-bounded basins and mountain ranges in Sonora and Chihuahua. Along the parallel, this province manifests in Nevada and western Utah through similar extensional tectonics that influenced the broader North American interior. Environmentally, the arid and semi-arid landscapes traversed by the 37th parallel in the southwestern United States, including elements of the Great Basin Desert, connect to desert ecosystems extending south across the border. The Sonoran Desert, which begins south of the parallel in southern Arizona and southeastern California, spans into northwestern Mexico, covering much of Sonora and parts of Baja California Sur with shared flora, fauna, and low-precipitation regimes driven by rain shadows from the Sierra Madre Occidental. Additionally, the California Current, a southward-flowing oceanic feature along the Pacific coast near the parallel's western extent in California, influences coastal climates and upwelling patterns that persist down to the Baja California peninsula, contributing to the region's persistent aridity and marine productivity.

Europe and Africa

Europe

The 37th parallel north intersects the European mainland in the southwestern tip of Portugal at Sagres Point in the Algarve region, a dramatic coastal promontory featuring cliffs and the historic Fortaleza de Sagres. From there, it proceeds eastward across the diverse landscapes of the Algarve, characterized by sandy beaches, limestone caves, and fertile valleys used for almond and fig cultivation, passing south of the towns of Lagos (37°06′N) and Albufeira (37°05′N). The parallel continues through the vicinity of Faro (37°01′N), the administrative center of the Algarve known for its marshlands and Roman ruins, before crossing the Guadiana River—the natural boundary with Spain—near Vila Real de Santo António (37°11′N). Entering Spain in the province of Huelva within Andalusia, the parallel traverses the coastal plains of the Costa de la Luz, renowned for strawberry fields and pine forests, passing south of Huelva city (37°15′N). It then moves through the province of Seville, skirting the southern outskirts of Seville (37°23′N), a hub of flamenco culture and Renaissance architecture amid expansive olive orchards. Further east, the route crosses the provinces of Córdoba and Jaén, winding through the undulating terrain of the Sierra Morena mountains' southern slopes, a biodiversity hotspot supporting cork oak woodlands and Iberian lynx habitats, with vast expanses of olive groves that produce much of Spain's olive oil. In the province of Granada, the parallel passes north of Granada city (37°10′N) and the iconic Alhambra fortress, traversing the fertile vega plains irrigated by the Genil River before ascending into the foothills of the Sierra Nevada, where almond blossoms color the landscape in spring. The line reaches the Mediterranean coast near Motril (36°45′N, close to 37° N), a subtropical fruit-growing area with banana plantations and proximity to the Costa Tropical's rugged shores. This segment of the 37th parallel exemplifies the Iberian Mediterranean climate zone (Köppen Csa), with average annual temperatures around 18°C (64°F) and precipitation concentrated in winter, fostering agriculture while contrasting with the arid interior plateaus to the north. The landscapes along this route highlight southern Europe's transition from Atlantic-influenced coasts to Mediterranean basins, with human settlements adapted to seismic activity in the Alpujarra region and historical trade routes linking Portuguese ports to Andalusian inland towns.

Africa and Mediterranean

From its entry into the Mediterranean Sea at the coast of Spain near Motril, the 37th parallel north arcs eastward between Spain and the Algerian coast before making landfall on Africa's northern extremity in Algeria around 6.25° E longitude. This brief crossing occurs along the coastal plain of the Tell region, a narrow strip of fertile lowlands backed by the Atlas Mountains, where the terrain transitions from sandy beaches to rolling hills supporting maquis shrublands and scattered olive groves typical of the Mediterranean biome. The local ecology reflects the broader North African coastal climate, with mild, wet winters and hot, dry summers fostering drought-resistant vegetation and diverse avian species.^[28] Reentering the Mediterranean Sea, the parallel skirts the Algerian-Tunisian border waters and enters the Gulf of Tunis, a semicircular bay indenting Tunisia's northern coast at approximately 37° N and 10.5° E. It then traverses the northeastern Cap Bon peninsula, a low-lying extension of limestone plateaus and coastal marshes near the city of Bizerte (37.27° N, 9.87° E), where ancient Phoenician ruins and modern ports dot the landscape amid citrus orchards and salt flats. The peninsula's geography highlights the parallel's insular character in this region, with shallow bays and capes influencing local fisheries and maritime trade routes.^[29]^[30]^[31] Eastward across the central Mediterranean, the parallel bisects the Strait of Sicily, a strategically vital waterway averaging 145 km wide and about 37° N latitude, separating the African mainland from the island of Sicily and facilitating the exchange of Atlantic and Levantine waters.^[32] On Sicily, it cuts through the southern and central parts of the island, traversing volcanic terrains shaped by Etna's activity (centered at 37.75° N) and expansive areas of terraced olive groves interspersed with maquis scrub. Key landmarks along this segment include the vicinity of Palermo in the northwest, though the line lies slightly south, and the ancient city of Syracuse on the southeastern coast (37.05° N, 15.29° E), underscoring the island's blend of rugged geology and agricultural heritage.^[33]^[34] Continuing its maritime arc, the parallel navigates the Ionian Sea toward Greece, approaching the Peloponnese peninsula's northern edge near Corinth (37.94° N, 22.88° E), where it grazes the Isthmus of Corinth amid olive-dotted hills and citrus plantations. Further east, it crosses the Aegean Sea, passing over islands like Sifnos (36.98° N, 24.73° E), a Cycladic outpost of barren hills, terraced fields, and maquis-covered slopes that exemplify the fragmented, insular geography defining this eastern Mediterranean reach. These island passages highlight the parallel's role in connecting volcanic archipelagos and peninsular extensions through dynamic sea lanes.^[35]^[36]

Asia

Middle East and Central Asia

The 37th parallel north traverses the Middle East and Central Asia through a diverse array of arid deserts, river valleys, and rugged mountain ranges, beginning in southern Turkey where it passes near Adana in the fertile Çukurova plain of Anatolia.^[37] This region features Mediterranean-influenced agriculture amid karst landscapes, before the parallel crosses into northeastern Syria around Qamishli, skirting the Jazira plateau's steppe-like terrains dotted with oases.^[38] In Syria, it approaches the upper reaches of the Euphrates River basin, influencing historical irrigation systems in the semi-arid Syrian Desert.^[39] Continuing eastward, the parallel enters northern Iraq along the Mesopotamian plain, passing through Kurdish territories near the city of Dohuk and crossing the Tigris River upstream of Mosul, where the river's floodplain supports ancient settlements amid transitioning to more arid zones.^[40] In Iraq, it skirts the edges of the Zagros foothills, highlighting the shift from riverine fertility to steppe grasslands before entering Iran. Within Iran, the line cuts through the northern central plateau and Elburz Mountains, coming within approximately 50 kilometers of the Caspian Sea's southern shore near Rasht and Bandar-e Anzali, where humid subtropical influences contrast the surrounding drylands.^[41] Further south in Iran, it navigates the arid Dasht-e Kavir near areas outside Tehran, emphasizing the plateau's vast salt flats and sparse vegetation.^[42] The parallel then proceeds into Turkmenistan, slicing through the expansive Karakum Desert's sandy dunes and gas fields south of Ashgabat, the capital city located just north of the line at about 37.95°N. Here, it approaches the Amu Darya River's lower course, where the river's delta oases provide vital water sources amid the hyper-arid environment, then briefly through southern Uzbekistan along the Amu Darya valley.^[43] Entering northern Afghanistan, the route follows the Hindu Kush's northern flanks near Kunduz province, traversing high-altitude valleys and arid steppes toward the Tajik border.^[44] In Tajikistan, it grazes the western Pamir Mountains' edges near Kulob, encountering alpine meadows and glacial tributaries before crossing briefly into northern Pakistan in Gilgit-Baltistan, characterized by barren highlands and intermittent wadis.^[45] This segment underscores the transition from desert basins to towering orogenic belts, with sparse settlements reliant on seasonal meltwater.^[46]

East Asia and Pacific

The 37th parallel north enters East Asia in the remote western deserts of China's Xinjiang Uyghur Autonomous Region, crossing arid landscapes near the city of Hotan at approximately 37.12°N, 79.92°E. This section of the parallel traverses the expansive Taklamakan Desert, characterized by extreme aridity and shifting sand dunes, before progressing eastward through the transitional steppes and plateaus of Gansu Province.^[47]^[48] In central China, the parallel skirts the northern edges of the Loess Plateau, passing close to Lanzhou in Gansu Province at around 36.03°N, 103.84°E, where it encounters the upper reaches of the Yellow River valley and semi-arid basins supporting limited agriculture and urban development.^[49] Continuing eastward, the parallel crosses the provinces of Ningxia, Shaanxi, Shanxi, Hebei, and into Shandong, transitioning from inland highlands to more fertile plains near the Yellow River basin in the east. It reaches the Shandong Peninsula's eastern coast near Yantai at approximately 37.47°N, 121.44°E, a port city known for its maritime significance and position along the Bohai Strait.^[50] From Yantai, the parallel extends into the Yellow Sea, a shallow marginal sea influenced by seasonal monsoons and tidal currents, before making landfall on the Korean Peninsula. In South Korea, the 37th parallel intersects Gyeonggi Province near Pyeongtaek at about 37.00°N, 126.99°E, a key industrial area south of Seoul amid the peninsula's central lowlands. It then traverses the rugged Taebaek Mountains and other ranges of the Korean Peninsula, characterized by forested highlands and narrow valleys that rise to elevations over 1,000 meters, before exiting into the Sea of Japan near the eastern coast around 37°N, 129°E. Although Busan lies slightly south at 35.18°N, 129.08°E, the parallel's path through southern Gyeonggi and nearby regions highlights proximity to major transport hubs and military installations in the vicinity.^[51]^[52] Crossing the Sea of Japan, the parallel reenters land on Japan's Honshu island in Ishikawa Prefecture, passing through central areas near Kanazawa at roughly 36.56°N, 136.62°E, amid the foothills of the Japanese Alps. This segment features volcanic terrain, hot springs, and coastal plains supporting rice paddies and historic castles, before descending toward the Pacific Ocean coast near Toyama Bay.^[53] In the open Pacific, the 37th parallel crosses the region influenced by the Kuroshio Extension, the eastward continuation of the warm Kuroshio Current that transports subtropical waters toward higher latitudes, affecting marine ecosystems, fisheries, and regional climate patterns.^[54]

Historical significance

American territorial organization

The Kansas-Nebraska Act of 1854 established the 37th parallel north as the southern boundary of the newly created Kansas Territory, extending westward from the Missouri border to the eastern boundary of New Mexico Territory, while the area south of this line remained designated as Indian Territory unless affected tribes consented otherwise.^[55] This division, which repealed the Missouri Compromise of 1820 and introduced popular sovereignty to decide the status of slavery in the territories, intensified sectional tensions and sparked violent conflicts known as "Bleeding Kansas," where pro- and anti-slavery settlers clashed over control of the region north of the parallel.^[55] The act's boundary choice reflected ongoing efforts to organize unceded lands for settlement and rail development, but it also preserved Native American holdings to the south, complicating future expansions.^[56] Upon Kansas's admission to the Union in 1861, the 37th parallel retained its role as the state's southern border, influencing the formation of adjacent territories and states in the American West. It defined the southern limits of Utah Territory (organized in 1850) and later Colorado Territory (1861), as well as Kansas, while serving as the northern boundaries for Arizona Territory (1863), New Mexico Territory, and eventually Oklahoma upon statehood in 1907.^[21] These alignments stemmed from congressional acts that extended the parallel westward to facilitate orderly settlement and resource allocation, culminating at the Four Corners region where it intersects the 109th meridian west, marking the only quadripoint in the United States.^[4] The parallel's straight-line demarcation also shaped the Cherokee Strip (or Outlet), a 60-mile-wide tract north of Indian Territory but south of Kansas, ceded by the Cherokee Nation in 1891 for white settlement via land runs, and the Oklahoma Panhandle, a narrow "No Man's Land" strip whose northern edge followed the 37th parallel due to discrepancies in earlier surveys excluding it from Texas or Kansas. Surveying efforts in the mid-19th century were crucial to delineating the 37th parallel amid the Public Land Survey System (PLSS), a rectangular grid of townships and ranges established under the Land Ordinance of 1785 and expanded westward to divide public domain lands into saleable parcels.^[57] Explorers and astronomers, including John C. Frémont, contributed through expeditions that mapped potential rail routes near the parallel; Frémont's 1853–1854 survey along the 38th parallel (adjacent to the 37th) provided critical topographic data for Congress's Pacific Railroad Surveys, informing boundary placements and PLSS extensions into arid western regions.^[58] These surveys, often using astronomical observations for latitude, integrated the parallel into the PLSS framework, where it aligned with baseline extensions from principal meridians like the Indian and New Mexico meridians, enabling precise cadastral mapping despite challenges from rugged terrain and Native land claims.^[21]

Other historical demarcations

The Damascus Protocol, drafted in 1915 by Arab nationalists and presented to Sharif Hussein bin Ali, proposed the establishment of an independent Arab state with its northern boundary aligned along the 37th parallel north, extending from the Mediterranean Sea eastward through Mersin-Adana in modern-day Turkey, then along the line to Birecik-Urfa-Mardin-Midiat-Jazirat ibn Omar-Amadiya to the Persian frontier.^[59] This demarcation was intended to define the extent of Arab independence in exchange for support in the Arab Revolt against the Ottoman Empire during World War I, reflecting strategic considerations for separating Arab territories from Ottoman Anatolia and Kurdish regions. Although the protocol's boundaries were not fully realized due to conflicting Allied agreements like the Sykes-Picot Accord, it marked a significant 20th-century reference to the 37th parallel in geopolitical negotiations for post-Ottoman territorial organization in the Middle East. In Central Asia, the 37th parallel approximated segments of historical trade and exploration routes, such as branches of the Silk Road connecting regions in modern-day Uzbekistan and Turkmenistan, though these alignments were not formally demarcated as boundaries but rather followed natural topography for practical transit.

Cultural and scientific aspects

Astronomical properties

The 37th parallel north serves as the approximate northern boundary for visibility of Canopus (α Carinae), the second-brightest star in the night sky with an apparent magnitude of -0.74, from locations in the Northern Hemisphere.^[60] Canopus, located at a declination of -52° 41′ 33″, theoretically becomes visible just above the horizon at latitudes up to about 37.3° N, though atmospheric refraction can extend this limit slightly northward to around 37.9° N under optimal conditions.^[61] At this parallel, observers can glimpse Canopus low on the southern horizon during winter evenings, provided skies are clear and free of light pollution. For northern celestial objects, the 37th parallel provides a vantage point where Polaris (α Ursae Minoris), the current North Star, culminates at an altitude of approximately 37° above the northern horizon.^[62] This altitude closely matches the observer's latitude due to Polaris's proximity to the north celestial pole (declination +89° 15′ 51″), making it a reliable reference for determining latitude in traditional navigation. Stars with declinations greater than 53° (calculated as 90° minus the latitude) remain circumpolar at this parallel, never setting below the horizon and tracing complete circles around Polaris throughout the night; prominent examples include most of Ursa Minor and parts of Draco and Cepheus.^[63] Solar phenomena at the 37th parallel exhibit mid-latitude characteristics, with significant seasonal variations in daylight duration but no occurrence of the midnight sun. The length of daylight on any given day can be calculated using the formula:

\text{Day length (hours)} = \frac{2}{15} \arccos\left(-\tan(\phi) \tan(\delta)\right)

where \phi is the latitude (37° N) and \delta is the Sun's declination, with angles in degrees; the factor $2/15 converts the angular hour angle to hours (since Earth rotates 15° per hour).^[64] At the summer solstice (\delta \approx +23.44^\circ), daylight lasts about 14.5 hours, while at the winter solstice (\delta \approx -23.44^\circ), it shortens to roughly 9.5 hours.^[64] The midnight sun, a 24-hour daylight period, is absent here because the parallel lies well south of the Arctic Circle (approximately 66.5° N), where the Sun's maximum declination exceeds the required threshold for continuous illumination. However, summer evenings feature extended civil twilights lasting up to 2-3 hours due to the Sun's shallow dip below the horizon, enhancing opportunities for astronomical observations.^[16] This latitude hosts or is near several notable astronomical observatories, facilitating studies of both southern and northern skies. The Lick Observatory on Mount Hamilton, California (37° 20′ N), exemplifies this, with its 36-inch Great Lick Refractor and other telescopes enabling research on stellar evolution and exoplanets from a site offering clear views toward Canopus in winter.^[65] Latitudinal comparisons highlight advantages over more southern sites like Kitt Peak National Observatory (31.96° N), where southern stars rise higher but northern circumpolar objects are lower in the sky, or Mauna Kea Observatories (19.82° N), which prioritize Southern Hemisphere access but miss low-northern phenomena visible at 37° N.

Paranormal associations and media

The 37th parallel north, particularly its traversal through the United States, has garnered significant attention in paranormal lore as "America's Paranormal Highway" or "UFO Highway," due to a reported high concentration of unidentified flying object (UFO) sightings, cattle mutilations, and cryptid encounters.^[66]^[10] This designation emerged prominently in the 2010s, highlighting anomalies such as the Joplin Spook Light in Missouri and Oklahoma, where unexplained luminous phenomena have been observed since the 19th century, and frequent UFO reports near Area 51 in Nevada, often described as darting lights akin to those in other global hotspots.^[66] Cattle mutilations, characterized by precise surgical excisions and exsanguination without tracks or struggle, have been documented thousands of times along this U.S. segment since the 1970s, with the FBI investigating clusters in states like Colorado, New Mexico, and Kansas during 1975.^[66]^[67] Cryptid reports, including Bigfoot-like entities and spectral figures such as La Llorona near the Colorado-New Mexico border, further contribute to the narrative of heightened strangeness.^[66]^[68] Investigator Chuck Zukowski's decades-long fieldwork, chronicled in Ben Mezrich's 2016 book The 37th Parallel: The Secret Truth Behind America's UFO Highway, details personal probes into these events, from livestock deaths in Colorado to alleged underground bases, positing a pattern of extraterrestrial or interdimensional activity.^[69]^[10] Similarly, Anthony Sanchez's UFO Highway (2011) maps UFO crash sites like Roswell and Aztec in New Mexico to the parallel.^[66] Recent analyses of National UFO Reporting Center (NUFORC) data suggest an elevated sighting density along this latitude compared to adjacent bands, with reports peaking in rural western states, though population and reporting biases influence interpretations. Sites like Skinwalker Ranch in Utah, slightly north but integrated into the lore, exemplify ongoing investigations into portals, orbs, and mutilations, as explored in related media.^[70] Media portrayals amplify these associations, often linking them to ancient alien theories. The History Channel's Ancient Aliens episode "The UFO Superhighway" (Season 20, Episode 8, 2024) examines UFO incidents, mutilations, and tribal lore along the parallel, suggesting it as an extraterrestrial corridor.^[71] The Science Channel's The Unexplained Files featured "Paranormal Highway of America" (2014), tracing anomalies from Nevada to Missouri.^[66] Fictional works, such as novels tying the parallel to global conspiracies, and ongoing series like The Secret of Skinwalker Ranch (2025 season), perpetuate the theme.^[72] Gaia publications, including a 2020s article on the "Paranormal Highway," extend connections to international anomalies, such as 1976 UFO sightings in Granada, Spain, and seismic events near Fukushima, Japan, both on the 37th parallel, implying a worldwide pattern.^[66]

References

[1]
Satellite map of 37th parallel north. Latitude: 37.0000 Longitude
The 37th parallel north is a circle of latitude that is 37 degrees north of the Earth's equatorial plane. Latitude: 37° 00' 0.00" N Longitude: 0° 00' 0.00" E
[2]
OK - Oklahoma - Senate.gov
The Senate passed the Kansas-Nebraska Act. As adopted on May 30, the law set the southern border of Kansas and thus, the northern border of Oklahoma at the 37 ...
[3]
[PDF] New Mexico v. Colorado, 267 U.S. 30 (1925). - Loc
Colorado & New Mexico on the 37th Parallel North Lati- tude," made in conformity to them. Several years later the Commissioner of the General. Land Office ...
[4]
Original Monument for Southwest Corner of Utah - Washington County
During the survey Mr. James established at the 37th Parallel North Latitude, the corner of Utah, Arizona, and Nevada, at mile 298 and 56.00 chains from his ...
[5]
[PDF] List of Cartographic Records of the General Land Office
... 37th. Parallel North Latitude from the 103 to 109° of Longit'.lde West from Greenwich estab lished and surveyed .•. by E. N. Darling U.S..
[6]
Where is Seville, Spain on Map Lat Long Coordinates
Seville, Spain is located at Spain country in the Cities place category with the gps coordinates of 37° 23' 33.1044'' N and 5° 59' 38.6592'' W.
[7]
Discover secret to longevity in Wendeng of China - Global Times
Sep 5, 2025 · Located at 37 degrees north latitude, Wendeng of China is the land of longevity embraced by mountains and seas. Meet the centenarians to ...
[8]
Taiyuan coordinates - Latitude, Longitude - Time-Ok
Where is Taiyuan. Taiyuan is located at latitude 37.8694 and longitude 112.56. City information. City, Taiyuan. Country, China. Population, 3,426,519 (2014).
[9]
[PDF] 19770020705.pdf - NASA Technical Reports Server (NTRS)
Gravity and magnetic anomaly profiles across the North American continent along the 37th North parallel of latitude were prepared for. €'. I and subjected to ...
[10]
The 37th Parallel makes strong case for UFOs - USA Today
Nov 6, 2016 · Along this desolate, largely uninhabited stretch of land, mysterious things have happened with eerie frequency. Strange flying objects.Missing: facts | Show results with:facts
[11]
The History of Geodes: Global Positioning Tutorial
Aug 12, 2024 · ... circumference of the Earth using the following equation: (360° ÷ θ) x (s). In this calculation, (s) is the distance between two points that ...
[12]
Degrees and ground distance - U.S. Fish and Wildlife Service
Mar 13, 2025 · This is found by the following formula*, where a is the equatorial radius (aka, semi-major axis) and b is the polar radius (aka, semi-minor axis):.
[13]
Learning Lesson: The Shadow Knows II - NOAA
Aug 1, 2023 · To solve for the circumference, multiply the distance from the equator by 360 and divide by the measured angle. The circumference around the ...
[14]
Climate Zones | National Oceanic and Atmospheric Administration
Jun 13, 2023 · This climate generally has warm and humid summers with mild winters. It extends from 30°-50° latitude mainly on the eastern and western borders ...
[15]
Comparative Lengths of Days and Nights
The longest day is longer than the longest night, and the shortest day is longer than the shortest night, for the reason that sunrise occurs when the upper edge ...
[16]
NOAA Improved Sunrise/Sunset Calculation
Selecting "Yes" in the Daylight Saving field will cause the resulting sunrise, sunset and solar noon times to be adjusted forward one hour. If you are ...Missing: 37 | Show results with:37
[17]
Land and Water versus Latitude - Av8n.com
The band between 30∘ and 60∘ north has 30% of the earth's area, while the corresponding band between 30∘ and 60∘ south has only 4%. The two bands are mismatched ...Missing: 37th | Show results with:37th
[18]
37th parallel north Facts for Kids
Oct 17, 2025 · Everything north of the 37th parallel became Kansas and Nebraska, and the land south of it remained Indian Territory.Missing: geography | Show results with:geography
[19]
[PDF] Boundaries of the United States and the Several States
The first Geological Survey record setting forth the history of the boundaries of the United States and the several States and Territories.<|separator|>
[20]
Shaping Nevada – NVBPELS
The first southern boundary of Nevada Territory was the 37th parallel, about 60 miles north of present Las Vegas. Nevada achieved its current southern limits on ...
[21]
Why the Four Corners Monument is in Exactly the Right Place
May 15, 2009 · ... 37 degrees North latitude. There, his meridian survey intersected the 1868 New Mexico-Colorado boundary survey, which ran along the 37th ...
[22]
Look-up Latitude and Longitude major cities in the USA
This table gives the latitude and longitude of various major cities in the United States. The first column gives the latitude in degrees and minutes.Missing: parallel | Show results with:parallel
[23]
Time Series: Guadiana Lower Estuary - NOAA
Guadiana Lower Estuary southwest Iberian Peninsula. Latitude: 37.1749 Longitude: -7.4078. Associated Investigators: Maria_Alexandra Teodósio ,
[24]
Algeria | Flag, Capital, Population, Map, & Language | Britannica
### Summary of Northern Coast of Algeria from Britannica
[25]
Tunisia | History, Map, Flag, Population, & Facts | Britannica
Tunisia is situated in the warm temperate zone between latitudes 37° and 30° N. In the north the climate is Mediterranean, characterized by mild, rainy ...Tunisia · Carthage · Daily life and social customs · Government and society
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GPS coordinates of Bizerte, Tunisia. Latitude: 37.2744 Longitude
Ras ben Sakka is the northernmost point of the African continent, located 15 kilometres to Bizerte, the northernmost city in Africa on the Mediterranean Sea.
[27]
GPS coordinates of Gulf of Tunis, Tunisia. Latitude: 37.0000 Longitude
GPS coordinates of Gulf of Tunis, Tunisia. Latitude: 37.0000 Longitude: 10.5000.Missing: degrees | Show results with:degrees
[28]
Where is Syracuse, Sicily, Italy on Map Lat Long Coordinates
Syracuse, Sicily, Italy is located at Italy country in the Cities place category with the gps coordinates of 37° 4' 31.7064'' N and 15° 17' 11.7096'' E.
[29]
GPS coordinates of Mount Etna, Italy. Latitude: 37.7551 Longitude
Mount Etna (Italian: Etna, Sicilian: Mungibeddu or a Muntagna, Latin: Aetna) is an active stratovolcano on the east coast of Sicily, Italy, in the Province ...
[30]
Strait of Sicily - Wikipedia
The strait is about 145 kilometres (90 mi) wide and divides the Tyrrhenian Sea and the western Mediterranean Sea, from the eastern Mediterranean Sea.<|separator|>
[31]
Where is Corinth, Corinthia, Greece on Map Lat Long Coordinates
The latitude of Corinth, Corinthia, Greece is 37.940880, and the longitude is 22.944860. Corinth, Corinthia, Greece is located at Greece country in the Cities ...
[32]
GPS coordinates of Sifnos, Greece. Latitude: 36.9833 Longitude
The village of Kastro (118), was the capital of the island during ancient times until 1836. It is built on top of a high cliff on the island's east shore and ...
[33]
Where is Adana, Turkey on Map Lat Long Coordinates
The latitude of Adana, Turkey is 37.000000, and the longitude is 35.321335. Adana, Turkey is located at Turkey country in the Cities place category with the gps ...
[34]
Map of Kamishli, Syria Latitude, Longitude, Altitude - climate.top
Latitude: 37°3' N. Longitude: 41° 13' E. Latitude & Longitude for Kamishli, Syria in decimal degrees: 37.05°, 41.22°. Altitude/ elevation: 455 m (1493 ft).
[35]
Tigris-Euphrates river system | Map, Basin, Irrigation, Mesopotamia ...
Oct 27, 2025 · The two rivers have their sources within 50 miles (80 km) of each other in eastern Turkey and travel southeast through northern Syria and Iraq ...Missing: 37th Turkmenistan Afghanistan Tajikistan Pakistan
[36]
GPS coordinates of Kurdistan, Iraq. Latitude: 37.0000 Longitude
Latitude: 37° 00' 0.00" N Longitude: 43° 00' 0.00" E. Nearest city to this article: Dihok · Read about Kurdistan in the Wikipedia Satellite map of Kurdistan ...
[37]
Map of Rasht, Iran Latitude, Longitude, Altitude - Climate.Top
Latitude: 37°19' N. Longitude: 49° 37' E. Latitude & Longitude for Rasht, Iran in decimal degrees: 37.32°, 49.62°. Altitude/ elevation: -9 m (-30 ft).
[38]
Where is Tehran, Iran on Map Lat Long Coordinates
The latitude of Tehran, Iran is 35.715298, and the longitude is 51.404343. Tehran, Iran is located at Iran country in the Cities place category with the gps ...
[39]
Amu Darya | River, Map, Delta, & Location | Britannica
The Amu Darya is one of the longest Central Asian rivers, formed by the Vakhsh and Panj rivers, flowing west-northwest, and is 879 miles long.Missing: 37th | Show results with:37th
[40]
Where is Kabul, Afghanistan on Map Lat Long Coordinates
The latitude of Kabul, Afghanistan is 34.543896, and the longitude is 69.160652. Kabul, Afghanistan is located at Afghanistan country in the Cities place ...
[41]
Kŭlob, Tajikistan geographical coordinates (latitude & longitude)
Where is Kŭlob. Kŭlob is located at latitude 37.9146 and longitude 69.7845. City information. City, Kŭlob. Country, Tajikistan. Population, 78,786 (2017).
[42]
Where is Hotan, Xinjiang, China on Map Lat Long Coordinates
Hotan, Xinjiang, China is located at China country in the Cities place category with the gps coordinates of 37° 7' 14.2752'' N and 79° 55' 23.2824'' E.
[43]
5.5-magnitude earthquake jolts Xinjiang: CENC - Xinhua | English ...
The epicenter, with a depth of about 8.0 km, was monitored at 37.58 degrees north latitude and 75.25 degrees east longitude. KEY WORDS:earthquake. YOU MAY LIKE ...<|separator|>
[44]
https://www.latlong.net/place/kunduz-afghanistan-14061.html
[45]
Yantai enchants world with fine wines - Shandong, China
Located at 37 degrees north latitude, Yantai in East China's Shandong province shines as one of the world's seven premier grape coastlines, combining sun ...
[46]
Pyeongtaek-si, Gyeonggi, South Korea
Latitude and longitude coordinates are: 36.992107, 127.112946. Pyeongtaek (평택시) is a large city located in the southwestern part of Gyeonggi Province in ...Missing: 37th | Show results with:37th
[47]
Where is Busan, South Korea on Map Lat Long Coordinates
The latitude of Busan, South Korea is 35.166668, and the longitude is 129.066666. Busan, South Korea is located at South Korea country in the Cities place ...
[48]
GPS coordinates of Kanazawa, Japan. Latitude: 36.6000 Longitude
Kanazawa (金沢市, Kanazawa-shi) is the capital city of Ishikawa Prefecture, Japan. Population: 458,937. Latitude: 36° 36' 0.00" N Longitude: 136° 37' ...Missing: parallel north
[49]
https://english.lanzhou.cn/system/2023/02/15/012357195.shtml
[50]
Kansas-Nebraska Act (1854) | National Archives
Jun 14, 2024 · Officially titled "An Act to Organize the Territories of Nebraska and Kansas," this act repealed the Missouri Compromise, which had outlawed ...
[51]
Kansas Territory and Its Boundary Question
The final boundaries for the state of Kansas were: In the south, the 37th parallel; for the east, the western boundary of Missouri; in the north, the 40th ...
[52]
[PDF] -1 IT IMF - NPGallery
Dec 30, 1997 · Kay County were part of the Cherokee Outlet, also known as the "Cherokee. Strip," a large reserve of land established in 1867 by treaty as a ...
[53]
[PDF] A History of the Rectangular Survey System
Albert White, U.S. Cadastral Surveyor, presents in this document a meticulous accounting of the vast story of public land surveying and registration. This ...
[54]
"Official Explorations for Pacific Railroads, 1853-1855." By George ...
In August, 1853, after the government surveys had been ordered, Fremont, with funds of his own, and Senator Benton's, planned his fifth expedition, to ...<|separator|>
[55]
Economic Cooperation Foundation: Damascus Protocol (1915) - ECF
The document contained the demands the Arab leaders wanted Hussein to present to the British in return for the Arabs revolting against the Ottoman Empire. The ...Missing: primary | Show results with:primary
[56]
Can you see Canopus, the 2nd-brightest star? - EarthSky
Feb 18, 2024 · To see Canopus, you must either be in the Southern Hemisphere or below the Northern Hemisphere's 37th parallel north. Enjoying EarthSky so far?
[57]
Let's Find Canopus! (February, 2017) | NAOJ
Feb 1, 2017 · The calculated northern limit when observing from flatland is approximately 37.9° north latitude. That is roughly the northern Fukushima ...
[58]
Latitude of Polaris - Javalab
In other words, for observers in the Arctic region, the latitude of the Polaris is 90°, and for the observer in the equator, the region is 0°. Therefore, if you ...
[59]
Circumpolar stars never rise or set and depend on latitude - EarthSky
Jun 3, 2025 · Circumpolar stars neither rise nor set but stay above the horizon at all hours of the day, every day of the year.
[60]
Sunrise and Sunset Times Near the Solstices
... latitude, in hours, is given approximately by. ts = 2/15 arccos (–tan φ tan δ). where φ is the latitude and δ is the Sun's declination. It is assumed that the ...<|control11|><|separator|>
[61]
Lick Observatory | airmass.org
Country, United States. Latitude, 37° 20' 36.00" N. Longitude, 121° 38' 12.00" W. Elevation, 1290m. Light pollution, bad. Limiting magnitude, 6.1.
[62]
America's Paranormal Highway Is Traced Through the 37th Parallel
Feb 20, 2025 · The 37th Parallel stretching from Virginia to California has more cattle mutilations UFO sightings paranormal events and unexplainable ...<|control11|><|separator|>
[63]
The Mysterious History of Cattle Mutilation
Apr 27, 2021 · Unexplained livestock mutilations have been reported for centuries ... Between April and October of 1975, nearly 200 cases of cattle mutilation ...
[64]
37th Parallel UFO and Paranormal Hotspots - Vortex Hunters
The paranormal activity along the 37th Parallel is not limited to UFOs. Reports of cryptids, such as Bigfoot, and unexplained phenomena like ghostly apparitions ...
[65]
The 37th Parallel: The Secret Truth Behind America's UFO Highway
... 37th Parallel or “UFO Highway.” So begins an extraordinary and fascinating journey from El Paso and Rush, Colorado, to a mysterious space studies company ...
[66]
Skinwalking the 37th Parallel - Chuck Zukowski - Apple Podcasts
Oct 8, 2020 · Known as the 37th Parallel North, or more generally as simply the 37th Parallel, it runs from Chesapeake Bay at the East to Santa Cruz at the ...
[67]
Watch Ancient Aliens Season 20 Episode 8 | HISTORY Channel
Mar 1, 2024 · Along the Earth's north 37th parallel there have been so many reports of unidentified flying objects, animal mutilations, and other mysterious events.
[68]
The Secret of Skinwalker Ranch - YouTube
Oct 14, 2025 · ... programming. Strange Energy Detected Above the Ranch (S1) | The Secret of Skinwalker Ranch. 48K views · 3 weeks ago ...more. HISTORY. 15M.<|separator|>