Benton Barracks was a Union Army military encampment, established during the American Civil War, in St. Louis, Missouri, at the present site of the St. Louis Fairground Park. Before the Civil War, the site was owned and used by the St. Louis Agricultural and Mechanical Association, which at the time was located on the outskirts of St. Louis. The barracks was used primarily as a training facility for Union soldiers attached to the Western Division of the Union Army.