The Coast Mountains are a major mountain range of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia. They are so-named because of their proximity to the sea coast, and are often referred to as the Coast Range. It includes volcanic and non-volcanic mountains and the huge icefields of the Pacific and Boundary Ranges, and the northern end of the notable volcanic system known as the Cascade Volcanoes. The Coast Mountains are part of a larger mountain system called the Pacific Coast Ranges or the Pacific Mountain System, which includes the Cascade Range, the Insular Mountains, the Oregon and California Coast Ranges and the Saint Elias and Chugach Mountains. The Coast Mountains are approximately 1,600 kilometres (990 mi) long and average 300 kilometres (190 mi) in width. ts southern and southeastern boundaries are surrounded by the Fraser River and the Interior Plateau while its far northwestern edge is delimited by the Kelsall and Tatshenshini Rivers at the north end of the Alaska Panhandle, beyond which are the Saint Elias Mountains, and by Champagne Pass in the Yukon Territory.