Lassen Peak, also known as Mount Lassen, is the southernmost active volcano in the Cascade Range. Located in the Shasta Cascade region of Northern California, Lassen rises above the surrounding terrain and has a volume of , making it one of the largest lava domes on Earth. It was created on the destroyed northeastern flank of now-gone Mount Tehama, a stratovolcano that was at least higher than Lassen Peak. It is part of the Cascade Volcanic Arc which stretches from southwestern British Columbia to northern California.