P.S. Duval & Son. "Military map of the United States & territories showing the location of the military posts, arsenals, Navy yards, & ports of entry." Map. Phila: P.S. Duval & Son, 1861. Norman B. Leventhal Map & Education Center, https://collections.leventhalmap.org/search/commonwealth:4m90f941n (accessed April 23, 2024).