The federal arsenal at St. Louis was established on this site in 1827, three miles south of the city, replacing aging Fort Belle Fontaine and supplying ordnance stores to Army and militia forces on the frontier while also fabricating ammunition, rockets, and artillery carriages and repairing weapons. By 1857 the 37-acre complex held about 25 buildings within a 10-foot-high stone wall, but city expansion made it seem hazardous and likely to be relocated until the Civil War intervened. After Abraham Lincoln's election in 1860 and the secession crisis, Missouri remained in the Union while seeking neutrality, yet Gov. Claiborne Fox Jackson, who favored secession, hoped eventually to secure the 40,000 arms stored there; the arsenal was nearly undefended, and commander Maj. William Bell had secretly agreed to surrender it to the state. In response, Congressman Francis P. Blair Jr. organized mostly German immigrant supporters as Union Guards, exposed Bell's intrigues, and helped remove him, though suspicion remained about his replacement, Maj. Peter Hagner. A decisive change came on Feb. 6, 1861, when Capt. Nathaniel Lyon arrived, allied with Blair, and pressed to secure the post; after Hagner resisted proper fortification, Lyon was placed in command of the defenses, the walls were strengthened, cannons emplaced, the small-arms arsenal mined for demolition, and patrols posted. After Confederate forces attacked Fort Sumter on April 12, 1861, Jackson refused Lincoln's call for Missouri troops, sought artillery from Jefferson Davis, and watched as secessionists captured the sub-arsenal at Liberty on April 20, encouraging St. Louis Minute Men to consider striking the arsenal. Blair then succeeded in replacing Gen. William Harney with Lyon, Washington authorized the arming of loyal citizens, and within a week 2,500 men enrolled in Blair's Union Guards and camped on the arsenal grounds. Lyon then sent most of the stored weapons to Illinois on April 27, including 21,000 small arms, 110,000 cartridges, and two cannons, leaving 10,000 muskets for his volunteers. Jackson shifted the militia muster to Camp Jackson at Lindell's Grove, where 700 militiamen assembled on May 6; when artillery secretly sent by Jefferson Davis arrived on May 8, Lyon surrounded the camp with 6,000 troops and forced its surrender on May 10, after which a riot in St. Louis left 28 people, mostly bystanders, dead. Throughout 1861 the arsenal served as Lyon's base, as a mustering place for new regiments, and as a prison and tribunal for accused spies and traitors, while continuing to provide ordnance; after Bull Run, it adapted old smoothbore muskets for Western volunteers and grew into the principal arms supplier in the Mississippi Valley. Expanded in 1863, it employed 700 civilians, including 150 children who made cartridges, and its wartime activity also benefited St. Louis through jobs, construction, and government contracts. After the war it became the major Western collecting point for returned and captured ordnance, with surplus sold, auctioned, or melted down, and in 1871 its role as an arsenal ended; it later served as a cavalry recruitment post, a quartermaster clothing depot, and a medical supply depot, and since 1952 it has produced maps and charts for the nation's military forces and intelligence agencies.
