The Allegheny Arsenal, established in 1814, was an important supply and manufacturing center for the Union Army during the American Civil War, and the site of the single largest civilian disaster during the war. It was located in the community of Lawrenceville, Pennsylvania, which was annexed by the city of Pittsburgh in 1868. Today, the site is the location of the nine-acre Arsenal Park as well as Arsenal Middle School, a county health services complex, and a large condominium development.