Cassius Fairchild (December 16, 1829-October 24, 1868) was a Wisconsin businessman, politician, and military officer. he was born in Franklin Mills, Ohio (now Kent, Ohio). Fairchild was educated mostly in Ohio. His father was Jairus C. Fairchild, who was the first Treasurer of Wisconsin and the first Mayor of Madison, Wisconsin. His brother was Lucius Fairchild, Governor of Wisconsin. He moved to Wisconsin and managed his family's cranberry and lumber businesses. He also managed their rental properties. Fairchild was elected to the Madison, Wisconsin Common Council where he served as president. He also served in the Wisconsin State Assembly. At the time of the American Civil War, Fairchild enlisted in the Union Army becoming a colonel in the 16th Wisconsin Volunteer Infantry Regiment. Fairchild was badly wounded in the Battle of Shiloh, and eventually died of his wounds.