Fort Cox, also known as Camp Wilkin, was built early in the fall of 1862 by Captain E. St. Julien Cox of St. Peter and his volunteer company of “frontier avengers.” Established by order of Colonel Charles E. Flandrau following the successful defense of New Ulm during the Sioux Uprising, it served as an advance outpost in a cordon of crude frontier forts extending from New Ulm to the Iowa border. Retained in 1863 as a link in a more westerly chain of fortifications, its small garrison was one of a number that helped patrol the Minnesota Indian frontier from Paynesville southward through Fort Ridgely and nine other posts to Fairmont. Small detachments of troops remained at these posts as late as 1865. Hexagonal in shape, two stories in height, and constructed of logs, the “strong and artistic fortification” was originally located on St. Paul Street, now Center Avenue.