High Quality Content by WIKIPEDIA articles! In the U.S. state of Utah, Interstate 15 runs north–south through the southwestern and central portions of the state, passing through many of the population centers of that state, including St. George, Provo, Salt Lake City, and Ogden, the latter three being part of the urban area known as the Wasatch Front. It is the primary north–south highway in Utah, as the majority of the state`s population lives along its corridor. The only Metropolitan Statistical Area in Utah not connected via I-15 is the Logan Utah-Idaho Metropolitan Statistical Area.