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.
Idaho State Highway 200
ID-200 is the westernmost portion of a chain of Highway 200s which extends east through Montana, North Dakota, and Minnesota. At only in length, Idaho's Highway 200 is the shortest in the chain while Montana's Highway 200 is the longest. There is another highway called SR 20 in Washington that would complete the chain of Hwy 200s, but ID-200 is no longer directly connected to WA-20. (The concurrency with US 2 from Newport/Oldtown to Ponderay was removed in the early 2010s, however the legacy of the concurrency continues with the mile markers from Ponderay to Montana.)