Mountain range, western U.S. A continuation of the Sierra Nevada , it extends north from Mount
Its highest elevation is Mount Rainier . Some of the summits, including Mount St. Helens , have erupted in the recent past. The {{link=Lewis and Clark Expedition">Lewis and Clark Expedition passed through the range in the Columbia River Gorge. Its northern continuation in British Columbia is known as the Coast Mountains. See also North Cascades National Park .