U.S. Route 81

U.S. Route 81 or U.S. Highway 81 (US 81) is a major north–south U.S. highway. It goes for in the central United States. It is one of the original United States Numbered Highways created in 1926 by the American Association of State Highway Officials.
The route of US 81 follows that of the old Meridian Highway which dates back as early as 1911. The highway has alternately (and unofficially) been known as part of the Pan-American Highway. In the part in the state of Oklahoma, the highway closely follows 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 endpoint is just north of Pembina, North Dakota, at the Canadian border.
Its southern endpoint is in Fort Worth, Texas, at an intersection with I-35W and US 287. Between 1926 and 1991, US 81's southern endpoint was at the Mexican border in Laredo, Texas. In 1991, the endpoint was moved to San Antonio.