Certainly the best known of Fort Snellingís buildings, this tower also may be the first. Built around 1820, it is now likely the oldest standing building in Minnesota. The Round Tower may have been designed as a site of last-ditch defense; its musket slits face even inside the fortís walls. Three stories tall, the tower mounted a 12-pounder field gun during the Winnebago Indian crisis of 1827. Later, it served as a guard house, wash house, coal storage building, ordnance storehouse, prison room, office, private home with a commercial beauty shop and museum.
Fort Snelling's flagpole was moved to the top of the tower in 1839, then moved again and a conical metal roof was added to the tower in 1861. A fire gutted the tower and consumed an adjacent commissary warehouse in 1869; stones reddened in the fire are clearly visible today.
For most of this century, the Round Tower and nearby South Battery were the only recognizable remains of the frontier fort.