Along with Highway 95 and Interstate 15, Highway 93 is one of the three main north-south highways crossing Idaho. It crosses the Continental Divide when entering Idaho from Montana, then follows the Salmon River south through Salmon as far as Challis. It then crosses the Challis National Forest to Arco, where it joins Highway 20 and Highway 26. Going SE past Craters of the Moon National Monument, it passes through Shoshone, proceeds directly south across Interstate 84 to Twin Falls and the Nevada border.
