The St Regis River begins at Lookout Pass in which mountain pass on the Idaho/Montana border?
Lookout Pass Lookout Pass is a mountain pass in the Rocky Mountains of the northwestern United States. In the Coeur d'Alene Mountains of the Bitterroot Range, the pass is on the border between Idaho and Montana, traversed by Interstate 90 (formerly U.S. Route 10) at an elevation of 4710 ft above sea level.
Bitterroot Range The Bitterroot Range is a mountain range and a subrange of the Rocky Mountains that runs along the border of Montana and Idaho in the northwestern United States. The range spans an area of 24223 mi2 and is named after the bitterroot ("Lewisia rediviva"), a small pink flower that is the state flower of Montana.