William Cogswell (15 July 1819-24 December 1903) was an American portrait painter from Fabius, New York. He taught himself to paint while working at a color factory in Buffalo during the 1830s, and he established himself in New York City before moving to California in 1873. He painted Presidents Abraham Lincoln (having attended the first of the Lincoln-Douglas debates) and Ulysses S. Grant, as well as Hawaiian royalty, during his lifetime.