Interstate 90 (I-90) is an east–west transcontinental Interstate Highway across the northern United States, linking Seattle to Boston. The portion in the state of Montana is 552.54 miles (889.23 km) in length, passing through 14 counties in central and southern Montana. It is the longest segment of I-90 within a single state.

Mineral County is a county located in the U.S. state of Montana. As of the 2020 census, the population was 4,535. Its county seat is Superior.