The Cascade Range is a mountainous region stretching from the Fraser River in British Columbia, Canada down to south of Lassen Peak, California. The Cascades (as they are called for short) are part of the Pacific Ring of Fire, the ring of volcanoes around the Pacific Ocean. All of the known historic eruptions in the contiguous United States have been from either Cascade volcanoes or near Mono Lake.: Lassen Peak was the last Cascade volcano to erupt in California, from 1914 to 1921. Lassen is the most southerly active volcano of the Cascade chain.