The Cassiar Mountains extend from the Yukon Territory 440 km southeast to the confluence of the Finlay and Fox rivers in north-central BC. Cassiar is thought to derive from KASKA, the name of a native group whose traditional territory lies in the mountains. The Stikine Ranges, with a central ridge of granite, rise to 2667 m. Peaks lower than 2000 m were rounded by glacial action. They have low relief and extensive tundra, owing to the area's severe boreal climate.

The Dease River attracted gold prospectors in the 1870s, and mineral exploration continues, but the mountains remain a remote part of BC. An ASBESTOS mine operated 1952-92, supporting the area's one community - the company town of Cassiar - now depopulated. An all-weather highway through the mountains opened in 1972.