Fort Ridgely was a United States Army outpost (1853–1867) near the Dakota reservation in southwestern Minnesota. Built between 1853–1854, it was named for three officers named Ridgely who were killed in the Mexican–American War. The fort played an important role in the Dakota War of 1862. The Battle of Fort Ridgely was fought there in two engagements over August 20–22, 1862 between Army volunteers and refugees from the Minnesota River valley, and Dakota forces.