Interstate 23 (I-23) is an Interstate Highway in the western United States. The southern terminus is in Flagstaff, Arizona at Interstate 240 (I-240). The northern terminus is in Mountainville, Utah at Interstate 80 (I-80), southwest near Great Salt Lake National Park (GSLNP). I-23 is only in the U.S. states of Arizona and Utah. I-23 is mostly parallel to its "sister route" and is the "brother route" of Interstate 21 (I-21) in the southern portion of the interstate. The largest metropolitan area I-23 connects to is Highway City, where it serves Routeville in Utah, while I-21 serves Intertropolis in Nevada. I-23 intersects I-48 at an interchange called the Routeville Interchange.
In Highway City, I-23 is locally known as Kimberly Blanding Highway. It serves as the main north-south expressway in Routeville, the eastern city of the metropolitan area of Highway City, and east of the Town Separator.
