The Four Corners Monument is the only point in the United States where four states meet: Arizona, Colorado, New Mexico and Utah. It sits on the Colorado Plateau on Navajo Nation land, off U.S. Highway 160 on New Mexico State Road 597, about 40 miles (64 km) southwest of Cortez, Colorado. A bronze disc set in granite marks the corner Congress defined as the crossing of the 37th parallel north and the 32nd meridian west of Washington, and four nearly straight state lines run out from it. Those lines were written into law along a parallel and a meridian, but the line that counts in court is the one surveyors staked out between 1868 and 1901. That quirk, confirmed by the Supreme Court in 1925, explains why the monument sits where it does.
The first marker here was a sandstone shaft. In 1875 Chandler Robbins, a surveyor for the General Land Office, was running the boundary between the Arizona and New Mexico territories northward from near the Mexican border. When his line reached the 37th parallel, it met the boundary Ehud N. Darling had already marked in 1868, and Robbins set his shaft at the junction. Every later marker has stood on that spot.
By 1899 the shaft had been broken, and surveyors Hubert D. Page and James M. Lentz replaced it with a new stone. A plain concrete pad went around it in 1912. In 1931 surveyor Everett H. Kimmell found that stone broken too and put in a brass disc set in concrete. The Bureau of Land Management and the Bureau of Indian Affairs poured a raised concrete platform around that disc in 1962, with the state lines and names laid in tile. The monument was rebuilt in 1992, when the 1931 brass marker gave way to the disc-shaped aluminium-bronze plate set in granite that visitors stand on today. A second rebuild in 2010 kept that 1992 plate in place.
Around the disc, the granite carries the seals of the four states and flags for the states and for the tribal nations. Read clockwise from Colorado, with two words in each state, the ring says "Here meet in freedom under God four states". Two tribal boundaries also meet here. The Navajo Nation, whose Parks and Recreation Department runs the site as Four Corners Monument Navajo Tribal Park and charges admission, holds the Arizona, New Mexico and Utah quadrants. The Colorado quadrant belongs to the Ute Mountain Ute Reservation, whose boundary follows the Colorado state line at the monument.
The site has a cold semi-arid climate. Temperatures have ranged from a record 105 °F (41 °C) to −18 °F (−28 °C). The nearest settlement of any size is Teec Nos Pos, Arizona, about 7 miles (11 km) to the southwest. It had 507 residents in 2020, and its trading post has been open since 1897.
East Along the Darling Line to the Preston Monument
Heading east, the 37th parallel divides Colorado from New Mexico. Ehud Darling surveyed it in 1868, and it is still called the Darling Line. The first landmark is close to the disc. The San Juan River, flowing west out of New Mexico past the volcanic neck at Shiprock, swings north and crosses briefly back into southwest Colorado. That stretch is within half a mile (0.8 km) of the quadripoint, and from there the river runs on into southeastern Utah. It is the main river draining the Four Corners region, and it historically divided Navajo country to the south from Ute country to the north.
Farther east the line crosses the reservoir on the same river. Navajo Lake lies mostly in San Juan and Rio Arriba counties in New Mexico, but its northern arm reaches into Archuleta County, Colorado. Each state runs its own shore, with Navajo Lake State Park in New Mexico and Navajo State Park in Colorado. Farther east, on the eastern side of the Sangre de Cristo Mountains, the line crosses Raton Pass, 7,834 ft (2,388 m) up between Trinidad, Colorado and Raton, New Mexico. Amtrak's Southwest Chief still crosses it on the old Santa Fe railway line.
The line ends on the High Plains at the Preston Monument, where Colorado, New Mexico and Oklahoma meet. The point was meant to be 37°N, 103°W, but surveys before 1900 never agreed on where that was. Levi S. Preston's 1900 marker became the legal tripoint in the 1925 Supreme Court case that also fixed the Darling Line.
North on the Colorado–Utah Line: Hovenweep to the Green River
The Colorado–Utah boundary heads due north from the disc along the 32nd meridian west of Washington. Rollin J. Reeves surveyed it in 1878. He began by finding Robbins's sandstone shaft and worked north from it. Not far north it crosses the Cajon Mesa, where Hovenweep National Monument spreads across both states between Cortez and Blanding. Its stone towers were built by Ancestral Puebloan farmers who left in the late 13th century, when the whole region was emptying out, possibly because of a 23-year drought.
Farther north comes the best-known flaw in Reeves's work. Near 38°16′34″N the border shifts about 1.5 miles (2.4 km) west of where the written description puts it. Because the markers are the law, that jog is still part of the state line, so the Colorado–Utah border is not actually straight.
Near its northern end the line runs through Dinosaur National Monument, at the meeting of the Green and Yampa rivers on the flank of the Uinta Mountains. Most of the monument is in Moffat County, Colorado, but the quarry that gave it its name is in Utah, north of Jensen. President Woodrow Wilson protected 80 acres around the quarry in 1915, and in 1938 the monument grew to 210,844 acres across both states. In the 1950s the Bureau of Reclamation planned a dam at Echo Park, inside the monument. After a national campaign against it, Congress passed the Colorado River Storage Project Act on 11 April 1956 without that dam. North of the monument the line reaches Wyoming.
West on the Utah–Arizona Line: Monument Valley, Lake Powell and Short Creek
West of the disc, the 37th parallel separates Utah from Arizona. Howard B. Carpenter surveyed this last side in 1901. Its eastern stretch crosses Navajo Nation land and runs straight through Monument Valley, called Tsé Biiʼ Ndzisgaii in Navajo, meaning "valley of the rocks". Its sandstone buttes rise up to 1,000 ft (300 m) above the valley floor, and the best-known ones stand right along the state line. The Navajo Nation regards the valley as sacred.
Next the line crosses Lake Powell, the reservoir that filled Glen Canyon after Glen Canyon Dam was completed on 13 September 1963. Most of the lake is in southern Utah, but the dam and a small part of the water are in Arizona. The town of Page, Arizona was built to house the people who built the dam. From here west, everything south of the line and north of the Colorado River is the Arizona Strip. It is larger than several U.S. states but has fewer than 10,000 residents, and the Grand Canyon cuts it off from the rest of Arizona.
Colorado City, Arizona (2,478 people in 2020) and Hildale, Utah (1,127) sit on either side of the line. They were once one settlement called Short Creek, founded in 1913 by a polygamist group that had broken away from the Latter-day Saints in search of a remote place to live. In 1953 Arizona Governor John Howard Pyle sent in troops in what became known as the Short Creek raid. The two towns still share one history on two sides of the parallel. Interstate 15 crosses the northwestern corner of the Strip, and the line ends where Utah and Arizona meet Nevada.
South on the Arizona–New Mexico Line: Window Rock, Lupton and the Gila
The southern side is the one Chandler Robbins surveyed in 1875, and it was the last of the four to be decided politically. When Congress created Arizona Territory in 1863, it split New Mexico along this meridian, extending the Colorado–Utah line south. The Confederate plan had divided New Mexico along the 34th parallel instead, which would have given the South a strip running from Texas to the Colorado River and on towards California. The Union line won, and that created the Four Corners.
Farther south, the line forms the eastern edge of Window Rock, Arizona, capital of the Navajo Nation and home of the Navajo Nation Council. Some buildings stand a few feet from New Mexico, and the village of Tse Bonito sits just across the line.
Just south of there, Interstate 40 crosses the line at Lupton, Arizona, a hamlet of 25 people in 2010, 21 miles (34 km) southwest of Gallup, New Mexico. Farther south the line leaves the plateau and drops into the Gila River valley. The town of Duncan, Arizona is 4 miles (6 km) west of it, and the Lazy B cattle ranch where Supreme Court Justice Sandra Day O'Connor grew up straddles the border. From there the line runs through desert ranch country until it reaches the Mexican border, where Robbins began.
Why the 1875 Stone Beat the Statute: New Mexico v. Colorado
The four surveys all had errors, because 19th-century instruments could not fix longitude precisely in remote desert. That left the states with a question: was the border the meridian and parallel Congress described, or the markers the surveyors actually set? New Mexico sued Colorado in 1919 over the Darling Line. In 1925 the Supreme Court ruled that the original survey markers are the border, even where they are off. The same principle covers the Four Corners Monument, the Preston Monument and the Colorado–Utah jog, so the legal descriptions of these borders now follow the markers rather than the numbers in the statutes.
The question came up again in 2009, when news reports claimed the monument was 2.5 miles (4.0 km) from where it should be. Those reports measured from the Greenwich meridian, which the United States adopted in 1912. The 19th-century surveys used the Washington meridian. A spokesperson for the National Geodetic Survey said the disc is roughly 1,800 ft (550 m) east of the spot Congress intended in 1863, and that because all four states accepted the 1875 survey, the monument is the legally binding corner. The Navajo Nation, which maintains the site, said the same.
Places where three countries rather than four states meet have their own disputes, and our guide to triple border points around the world covers several. For the landscape around the disc, see the Four Corners region geography guide or read more about the buttes on the Utah–Arizona line in our Monument Valley guide.