Question: John Mullan, Jr. (July 31, 1830 – December 28, 1909) was an American soldier, explorer, civil servant, and road builder, heled the construction crew which built which road, was the first wagon road to cross the Rocky Mountains to the Inland of the Pacific Northwest, in Montana, Idaho, and Washington state, between the spring of 1859 and summer 1860?  
Sentence (from "Mullan Road"): Mullan Road was the first wagon road to cross the Rocky Mountains to the Inland of the Pacific Northwest.
Relevant evidence: Yes