The Rocky Mountains, west of the Great Plains, extend north to south across the country, peaking around in Colorado. Farther west are the rocky Great Basin and deserts such as the Chihuahua and Mojave. The Sierra Nevada and Cascade mountain ranges run close to the Pacific coast, both ranges reaching altitudes higher than . The lowest and highest points in the contiguous United States are in the state of California, and only about apart. At an elevation of , Alaska's Denali is the highest peak in the country and in North America. Active volcanoes are common throughout Alaska's Alexander and Aleutian Islands, and Hawaii consists of volcanic islands. The supervolcano underlying Yellowstone National Park in the Rockies is the continent's largest volcanic feature.