The Insular Mountains are rugged, particularly on Vancouver Island where peaks in Strathcona Provincial Park rise to elevations of more than 2,000 m (6,562 ft).

[1] These Insular Mountains are not yet fully emerged above sea level, and Vancouver Island and the Haida Gwaii are just the higher elevations of the range, which was in fact fully exposed during the last glacial period (maximum ice extent about 18,000 years ago) when the continental shelf in this area was a broad coastal plain.

Glaciers that ran down to the Pacific Ocean sharpened the valley faces and eroded their bottoms.

Ice Age remnants may still be noted, such as the Comox Glacier in the Vancouver Island Ranges.

The Elk River Mountains, located in Strathcona Provincial Park, are sometimes classified as a range.