Charleston Harbor and its approaches showing the positions of the Rebel batteries

Anticipating war, the U.S. Coast Survey was one of the few agencies able to provide accurate nautical charts and topographic maps before and during the war. Led by Alexander Dallas Bache, the nation’s foremost scientist and great-grandson of Benjamin Franklin, the agency’s primary mission was to chart the nation’s coastal waters, and by the 1850s was beginning to produce detailed nautical charts for most of the Atlantic and Gulf coastal waters. One example is this chart of South Carolina’s Charleston Harbor published in 1863. Utilizing an 1858 chart, which was based on detailed hydrographic and topographic surveys conducted in the early 1850s, this version was overprinted to show forts, “National“ and “Rebel“ trenches and batteries, and positions of the attacking fleet as of September 7, 1863.
Courtesy of Boston Public Library