As the frontier moved westward, Fort Ridgely declined in importance. Troops were withdrawn on May 22, 1867, but the buildings and land remained federal property. Settlers pillaged the fort, hauling away stone, wood, and other materials; squatters turned the commissary into a barn, and even the massive stone barracks, more than 200 feet long and two stories high, was torn down. Despite army threats to remove them, illegal homesteaders eventually petitioned for ownership of the lands they occupied, and legal title was granted in 1874. The Minnesota Historical Society began archaeological excavations at Fort Ridgely in 1936, uncovering eight building sites and exposing stone foundations visible today. The excavations also revealed a long history of Indian occupation before the fort was built. After the excavations were completed, the commissary was rebuilt and used as a museum and assembly hall.