P.S. Duval & Son. "Military map of the United States & territories showing the location of the military posts, arsenals, Navy Yards, & ports of entry. Compiled from pub-doc--1861." Map. Philadelphia: Published by P.S. Duval & Son, 1861. Norman B. Leventhal Map & Education Center, https://collections.leventhalmap.org/search/commonwealth:kk91fs92j (accessed July 01, 2022).