The Washburn Observatory is an astronomical observatory located at 1401 Observatory Drive on the University of Wisconsin–Madison campus in Madison, Wisconsin, United States. Completed in 1881, it was a major research facility for about 50 years. Today, it is home to the UW-Madison College of Letters and Science Honors Program, while the telescope remains in use by students in introductory astronomy courses and the general public during open houses and viewings.

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.