In 1986, U.S. Route 10 was replaced in Montana by Interstate 90. This caused the removal of the concurrent U.S. Route 10 Alternate numbering from MT 1. In 2000, the portion of MT 1 traveling from modern mileposts 48.107 to 62.322 was reconstructed to the current routing. In 2008, the small portion traveling from mileposts 10.058 to 16.756 was reconstructed. The route has not been changed since.