segment of the Pacific mountain system that extends generally northward and eastward in an arc for about 400 miles (650 km) from the Aleutian Range to the Yukon boundary in southern Alaska, U.S. Mount McKinley (McKinley, Mount), which reaches an elevation of 20,320 feet (6,194 metres), near the centre of the range, in Denali National Park and Preserve, is the highest point in North America. Many nearby peaks exceed 13,000 feet (4,000 metres), including Mounts Silverthrone, Hunter, Hayes, and Foraker. Drained by the Yukon River (north) and the Pacific Ocean (south), the mountains separate the interior tundra from the Pacific coastal region. The peaks present many challenges to climbers, and tourists are attracted by the enormous glaciers and Arctic scenery. The range is crossed at Isabel Pass by the Trans-Alaska Pipeline en route to its southern terminal at Valdez. See also Alaskan mountains.