A map of the Charleston Harbor, South Carolina, site of the Battle of Fort Sumter (April 12-13, 1861) at the outbreak of the American Civil War. The map shows the city of Charleston and railroads, the Union held Fort Sumter at the mouth of the Charleston Harbor, Confederate held Fort Moultrie on Sullivan's Island on the northern approach to the harbor, and Confederate held Fort Wagner on Morris Island on the southern approach to the harbor.