The Purcell Range is shaped somewhat like a wedge that is bordered on the east by the north-northwest trend of the Rocky Mountain Trench (Columbia and upper Kootenay Rivers) and the nearly north to south trend of the Purcell Trench (Beaver and Duncan Rivers, and Kootenay Lake). The Canadian Rocky Mountains are to the east and the Selkirks to the west. Geologically, the Purcells extend south into the United States within the great bend of the Kootenay River. The river then returns north to Canada, turns west and joins the Columbia River.
The high summits of the Purcells tend to be on the west side of the range above the Purcell Trench near the Selkirks, and approaches are often up long, drier canyons on the east slopes. The steeper, shorter western slopes bear the brunt of storms and are more heavily overgrown. The northern section of the Purcell Range is composed mostly of sedimentary and metamorphic rocks. The more famous climbing on the high granite summits of the Conrad, Vowell and Bugaboo Groups, the biggest uplift in the Mount Farnham area (metamorphic rocks) and the southern end of the range are not included in this section.