They are located on the west side of the Rocky Mountain Trench in the area of the Columbia Valley, and on the east side of the valley of Kootenay Lake and the Duncan River.

[4][5] The only large settlements in the mountains are the Panorama Ski Resort and Kicking Horse Resort, adjacent to the Columbia Valley towns of Invermere and Golden, though there are small settlements, such as Yahk and Moyie along the Crowsnest Highway, and residential rural areas dependent on the cities of Creston, Kimberley and Cranbrook, which are located adjacent to the range..

The Purcells are shown on some United States maps as the Percell Mountains, where their southern limit protrudes into the states of Idaho and Montana, abutting Lake Koocanusa, a reservoir on the Kootenai River.

[6] American geographic classifications consider the Percells to be part of the Rocky Mountains but in Canada that terminology is reserved for ranges on the east side of the Rocky Mountain Trench.

The Purcell Supergroup rocks that make up the Purcells were formed in the Proterozoic eon (in the Precambrian period), which spans from 2,500 million years ago to about 540 million years ago.