Washburn County is a county in the U.S. state of Wisconsin. It is named after Governor Cadwallader C. Washburn. As of the 2020 census, the population was 16,623. Its county seat is Shell Lake. The county was created in 1883.

Cadwallader Colden Washburn was an American businessman, politician, and soldier who founded a mill that later became General Mills. A member of the Washburn family of Maine, he was a U.S. Congressman and governor of Wisconsin, and served as a general in the Union Army during the American Civil War.