List of Interstate Highways in Utah
The Interstate Highways in Utah are maintained by the Utah Department of Transportation (UDOT). The Interstate Highway System is a nationwide system with only a small portion of these routes entering Utah. Originally, the State Road Commission of Utah, created on March 23, 1909 was responsible for maintenance, but these duties were rolled into the new UDOT in 1975. There are of Interstates within the state. The longest is Interstate 15 (I-15) at and the shortest is I-215 at . One unique former route is Interstate 415, which was never signed as such, and was only used as a temporary designation for the eastern portion of what is now the Interstate 215 belt loop around Salt Lake City.
Transportation in Appalachia
The next great leap in transportation was the creation of the U.S. Highway system in 1926, replacing the auto trails. The longest primary US highway contained in Appalachia is US 11 traversing the eastern side. US 21 was another primary US highway, but much of its route has been decommissioned and replaced with Interstate 77. These make/made up the north-south routes. East-west routes include US 30, US 33, US 40, US 50, US 60, and US 70. Many spur routes such as US 220 and US 119 serve various parts of Appalachia.