William Henry Barnes (April 5, 1885 - September 25, 1973) was a member of the Wisconsin State Assembly.
Barnes was born in Lisbon, Juneau County, Wisconsin, on April 5, 1885. On September 25, 1973, Barnes died in New Lisbon, Wisconsin. He is buried there.
Barnes was a member of the Assembly from 1935 to 1940. He was a member of the Wisconsin Progressive Party.