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.
List of U.S. Highways in Utah
The U.S. Highways in Utah are painted by the Utah Department of Transportation (UDOT). The United States Numbered Highway System is a nationwide system with only a small portion of its 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 U.S. Highways in the state. The longest is U.S. Route 89 at and the shortest is U.S. Route 89A at . Five former U.S. Highways exist in the state of Utah, all of which have been replaced by current interstate and U.S. Highways, with the most recent change being U.S. Route 666 redesignated as U.S. Route 491 in 2003.