Jefferson Barracks was established as a military post in 1826 when it was determined that Fort Belle Fontaine was considered to be unhealthy and unsatisfactory as a military post. The town of Carondelet, anxious to attract business, offered the town common fields to the military. On October 23, 1826, the war department declared the post to be named Jefferson Barracks in honor of President Thomas Jefferson who died six days prior to the founding of the post. The location of Jefferson Barracks near St. Louis and on the Mississippi River proved to be an excellent site for a permanent military post.
Few military installations have been as important to the United States as Jefferson Barracks. Soldiers from the post have served in every major war through World War II. The entire history of Jefferson Barracks is displayed at the Powder Magazine Museum.
During the Mexican War, Jefferson Barracks was a major distribution point for men and materials destined for the West. The post also served as a major training, deployment and medical center during the Civil War. During WWI and WWII it was used primarily as an induction and training center for soldiers entering the army in preparation for active duty.
The post was deactivated in 1946, although a military presence has been maintained on a section of the post by the State of Missouri for the Missouri Air National Guard and the Missouri Army National Guard to this day. Beginning in 1950, the Federal Government conveyed a tract of land to St. Louis County to operate as a historical park
The park offers shelter and picnic sites, trails, wedding sites, a disc golf course and an archery range as well as multiple athletic fields. The museums operated by St. Louis County include the Laborer’s House and Ordnance Stable, both built in 1851. These are among the oldest extant structures of Jefferson Barracks. The Ordnance Room was also built in 1851. It features rotating exhibitions on the history of this site and the United States military. The Powder Magazine Museum was built in 1857 and is the only museum that tells the whole story of the history of Jefferson Barracks. In addition to the museum buildings operated by the County, visitors will find the Missouri Civil War Museum, as well as, several new museums that are in the works such as the Jefferson Barracks Telephone Museum, the POW-MIA Museum and the Jefferson Barracks Ordnance Depot Museum.
The new Pavilion at Lemay is a 42,000 square foot recreation center located inside Jefferson Barracks Park. It features and indoor track, fitness area, multi-purpose gymnasium, meeting rooms and a child care area. Its pool includes a lazy river and attracts numerous visitors in the swimming season.
Jefferson Barracks Park is part of the Mississippi River Greenway, a 110-mile network of pedestrian and bicycle trails connecting the St. Louis region.