U.S. Route 81

U.S. Route 81
US 81 highlighted in red
Route information
Length	1,220 mi[citation needed] (1,960 km)
Existed	1926–present
Major junctions
South end	I-35W / US 287 at Fort Worth, TX
Major intersections	I-44 at Chickasha, OK I-40 at El Reno, OK I-135 from Wichita, KS to Salina, KS I-70 near Salina, KS I-80 at York NE I-90 at Salem, SD I-29 from Watertown, SD to Manvel, ND I-94 / US 52 at Fargo, ND US 2 at Grand Forks, ND I-29 from Joliette, ND to Pembina, ND
North end	I-29 / PTH 75 at Pembina–Emerson Border Crossing near Pembina, ND
Location
Country	United States
States	Texas, Oklahoma, Kansas, Nebraska, South Dakota, North Dakota
Highway system
United States Numbered Highway System List Special Divided
← US 80 → US 82

U.S. Route 81 or U.S. Highway 81 (US 81) is a major north–south U.S. highway that extends for 1,220 miles (1,960 km) in the central United States and is one of the original United States Numbered Highways established in 1926 by the American Association of State Highway Officials.

The route of US 81 follows that of the old Meridian Highway (so called because it roughly followed the Sixth Principal Meridian of the US Public Land Survey System) which dates back as early as 1911.^[1] The highway has alternately (and unofficially) been known as part of the Pan-American Highway.^[2] In the segment in the state of Oklahoma, the highway closely corresponds to the old Chisholm Trail for cattle drives from Texas to railheads in Kansas in the 1860s and 1870s.

As of 2004, the highway's northern terminus is just north of Pembina, North Dakota, at the Canadian border. At this point, it is routed along Interstate 29 (I-29) and continues northward into Manitoba on Highway 75, which leads to Winnipeg.

Its southern terminus is in Fort Worth, Texas, at an intersection with I-35W and US 287. Between the inception of the numbered highway system in 1926 through 1991, US 81's southern terminus was at the Mexican border in Laredo, Texas. In 1991, the terminus was moved to San Antonio. The route was shortened to its present length of 1,234 miles (1,986 km) in 1993, when the terminus was moved to Fort Worth. In both cases, the dropped portions of US 81 were replaced by I-35.^{[citation needed]} Portions of former US 81 south of Fort Worth continue to exist as business loops of I-35; a section from Hillsboro to Fort Worth exists as State Highway 81.

The decommissioning of portions of US 81 that have been displaced by concurrent Interstate Highways means that US 81 no longer extends from the Canadian border to the Mexican border, while one of its auxiliary routes, US 281 does extend to both borders. As a result of decommissioning portions of US 81, the length of US 81 is actually 672 miles (1,081 km) miles shorter than US 281.