CSA 11, 10¢ dark blue (4 margins) tied RICHMOND Va. CDS on small commercially-made envelope to Frank J. Davidson Esq, Charleston Arsenal, Charleston, S.C.  $125.

Charleston Arsenal was a U.S. Army arsenal seized by state militia at the outbreak of the war. It was constructed between 1825 and 1832 by the U.S. government. The Charleston Arsenal produced a considerable amount of artillery and small arms ammunition during the Mexican-American War and up to the Civil War. With the secession of South Carolina in December 1860, the Arsenal became a target for Charleston militia. South Carolina troops seized the arsenal in late December, and held it for much of the war. Josiah Gorgas had the arsenal enlarged and modernized with the installation of steam power. For a time, it was used a barracks to house Confederate troops, including the 26th South Carolina. The arsenal was retaken by U.S. troops in 1865 when Charleston finally fell.