Question: What mountain range was crossed by the wagon road that connected Fort Walla Walla to the fort established in 1846 in Montana?
Sentence (from "Mullan Road"): It led from Fort Benton, which at the time was in the Dakota Territory, then Idaho Territory from July 1863, and Montana Territory beginning in May 1864, and the navigational head of the Missouri River (and once farthest inland port in the world).
Relevant evidence: Yes