Brevet Brigadier General Lester Sebastion Willson, (June 16, 1839 – January 26, 1919), was a U.S. Civil War officer in the Union Army, Assistant Quartermaster General of New York, and a Montana merchant and politician in Bozeman, Montana. He was married at Albany, N.Y., on March 2, 1869, to Miss Emma D. Weeks, a native of Vermont. He died in Bozeman, Montana on January 26, 1919.