A prime example of a sea fortress, Sumter was a giant brick pentagon built on an artificial atoll of rock in the middle of Charleston’s shipping channel, surrounded on all sides by water. The nearest land was Morris Island, three-quarters of a mile due south; Charleston’s famous Battery esplanade was three miles to the northwest. The rocks themselves compounded South Carolina’s resentment of the fort: These were Northern rocks, granite from quarries in New York and New England.
