Jefferson Barracks was established as a military post in 1826 when it was determined that Fort Bellefontaine 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. Men from the post have served in every major war. 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. That is the primary mission of Jefferson Barracks. In 1971 Jefferson Barracks County Park, the adjacent active military base, and several other adjoining land parcels were placed on the National Register of Historic Places.

All the buildings owned by the County in this district are considered to be historically significant.

The County added 233 acres to the park in 1960, using, in part, funds from a 1954 bond issue for landfill sites. The south central section of the park was leased to a series of private companies to operate as a landfill, and eventually about 72 acres was used for this purpose until 1971. The resulting methane and other gases have remained a continuing problem for the park. The 1986 Bond Issue called for the development of a Veterans Memorial at Jefferson Barracks that was completed in 1990 as designed by Team Four Architects. This is manifested in the Jefferson Barracks Veterans Memorial Amphitheater that hosts historical programs, concerts and many other activities.

A volunteer support group for the park, the Friends of Jefferson Barracks, was organized about 1983, and they operate the gift shop and concessions to raise money for park activities. The Friends also began publication in 1993 of a quarterly newsletter, called the Jefferson Barracks Gazette. They aided in the restoration of the 1878 Ordnance Barn, which had been reduced to its stone basement by the Army in 1946, for use as the Jefferson Barracks Visitor’s Center. From 2000 to 2003 the frame superstructure was reconstructed to serve as an education center and community facility, a longtime goal of the Friends. It was financed by a wide array of county, state and federal sources, including the National Recreation Trail Program and the Economic Development Initiative Program of the U.S. Department of Housing and Urban Development, as well as from the Friends.

In 1995, the 3-mile Dennis Schick Trail was built with grant funds from the National Recreation Trail Program and L&WCF. Jefferson Barracks Park has now become a Land & Water park and is subject to Section 6(f) restrictions.

Jefferson Barracks is the most heavily programmed park in the county system including Living History programs, Civil War and World War II reenactments, concerts, cross country and benefit runs, and many other activities. The park offers reservable 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 Laborers House currently exhibits how the building may have appeared when an officer and his family lived there in the 1870s. Behind the Laborers House is an attractive garden maintained by volunteers and is used for historic programs and weddings. 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 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 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. It’s attractive pool includes a lazy river and attracts numerous visitors in the swimming season.

Jefferson Barracks Park is included in the Mississippi River Greenway.