Established in 1859, the San Antonio Arsenal supplied the entire western frontier of the antebellum United States. When the Army Corps of Engineers selected this site along the San Antonio River, San Antonio was the last major supply point before the vast, largely unmapped frontier stretching west to California. The arsenal manufactured and stored ammunition, repaired weapons, and outfitted the cavalry and infantry units that staffed the string of frontier forts — Fort Clark, Fort Inge, Fort Davis, Fort Bliss — that the Army built to protect settlers from Comanche and Apache raids along the western roads.
At the outbreak of the Civil War in 1861, Texas state forces seized the arsenal before federal troops could secure or destroy it — a significant early act of secession in the Southwest. Confederate forces used the arsenal's supplies throughout the war. After the Union restored control in 1865, the arsenal resumed its frontier supply mission, playing a role in the Army's campaigns against the Comanche and Apache through the 1870s and 1880s.
The original limestone buildings, with their elegant Federal-style architecture that seems slightly improbable for a weapons depot on the frontier, have survived and now house offices. The thick walls that once kept gunpowder dry still stand.