It joins the Rocky Mountain Trench another 50 miles (80 km) northward at the south tip of Kinbasket Lake, in British Columbia.

[3] The Priest River complex in northern Idaho, northeastern Washington, and southeastern British Columbia is a series of early and middle Eocene metamorphic core complexes that extend southward from the south-central Canadian Cordillera to the Columbia Plateau and southeastward to the Idaho Batholith.

The southern segment, which extends from Lake Coeur d'Alene through Sandpoint to north of Colburn, contains compelling evidence of the east-dipping Purcell Trench normal fault.

[1] The width and depth of the inner valley of the Kootenai River in Boundary County, Idaho, when the first glaciers arrived is unknown.

This allowed hundreds of feet of fine-grained, silty sediment to deposit in the Purcell Trench and create the flat terraces seen today near Bonners Ferry.