It is present in an area of about 15,000 km2 (5,800 sq mi) in southwestern Alberta and southeastern British Columbia, Canada, and it extends into the northwestern United States where it is called the Belt Supergroup.

[2] Fossil stromatolites and algal structures are common in some of the Purcell Supergroup rocks,[3][4] and the Sullivan ore body at Kimberley, British Columbia, a world-class deposit of lead, zinc, and silver, lies within the Alderidge Formation in the lower part of the Purcell.

[7] The Purcell Supergroup consists primarily of argillites, carbonate rocks (limestone and dolomite), and quartzites, and includes localized occurrences of igneous rocks (mafic lava flows, tuffs, pillow basalts, and gabbroic and dioritic sills and dykes).

[1] In the southern Canadian Rockies (Waterton Park area), the supergroup is subdivided as follows: [1][8][9] In the southern Purcell Mountains (Cranbrook area), the supergroup is subdivided as follows: [4] The Purcell Supergroup was probably deposited in subsiding deltaic to marine environments along the margin of the North American craton,[10] possibly in an intracratonic basin where North America and another landmass were joined in a supercontinent called Columbia/Nuna.

[1] The now-closed Sullivan Mine at Kimberley, British Columbia, worked a world-class sedimentary exhalative (SedEx) deposit that is hosted in the lower part of the Purcell Supergroup.