Mount Williamson is a major Sierra Nevada summit in eastern California, rising 14,379 feet and ranking second in both the range and the state after Mount Whitney. In the John Muir Wilderness of Inyo National Forest, it stands near Owens Valley yet remains notably remote, with a dramatic 8,000-foot drop in 4 miles that makes it especially imposing. Named for Lieutenant Robert Stockton Williamson, it entered climbing history with recorded ascents beginning in 1884 and additional routes established through the 1980s. Despite technically varied routes, long approaches and great elevation gain shape the challenge, while nearby habitat also supports rare California bighorn sheep.