Bad Rock Trail in northwest Montana was an important route for the aboriginal people of the region. The first documented account of it came from North West Company trader David Thompson in 1809, when, from near the company's Saleesh House trading post, he reported that the trail was the scene of many battles among the Kootenai, Salish, and Blackfeet people. In the years that followed, it became a much cursed obstacle on the road up the Clark Fork and was traveled by western figures including Isaac Stevens, John Mullan, and William A. Clark. After crossing Bad Rock in 1841, Father Pierre-Jean DeSmet wrote that although he had seen landscapes of awful grandeur before, this one surpassed all others in horror and caused his courage to fail at first sight. In 1883, the Northern Pacific Railway blasted away portions of the trail to complete its transcontinental line, and in 1936 the Montana Department of Transportation repeated the process while constructing this segment of highway. Bad Rock Trail remains a commanding presence on Highway 200 in northwest Montana.