Area: 62734 sq km.
Location: Not to be confused with its smaller component, the Bitterroot Mountains, the Bitteroot Range spans Central Idaho and the area of the Idaho-Montana border southwest from Missoula, as far west as the Snake River. They are formally limited by the Salmon River but extend SE along the Continental Divide east of the Lemhi River. Their major components are the aforementioned Bitterroot Mountains, the similarly-sized Clearwater Mountains to the west, the smaller Coeur d'Alene Mountains and St Joe Mountains on the NW, and on the southeastern 'tongue' along the Continental Divide include the Beaverhead Mountains. Adjoining areas not formally part of the Bitterroot Range, including the Lemhi Range, Salmon River Mountains, and Pioneer Range, may eventually be included in this regional description even though they are not formally part of the Bitterroots. The Bitterroots occupy a similar position in the US relative to that of the Selkirks and Purcells in British Columbia; the southern limits of the Selkirks border the Coeur d'Alene Mountains on the north.
History: Adjusted boundary in area of Gibbons/Big Hole/Lost Trail Passes to make wider "channel" between the Beaverhead Mountains and Bitterroot Mountains; formal boundary appears to be Lost Trail Pass but Gibbons Pass chosen instead; prominence boundaries follow Gibbons and Big Hole Passes MC