Since the American Revolution, Americans have built systems of forts at harbors along the coast to strengthen maritime defenses. Following the War of 1812, several major weaknesses in the American coastal defense system were identified. To fill these voids, Congress and the US Army Corps of Engineers planned the construction of forty-two forts, primarily located along the Atlantic and Gulf coasts from Maine to Louisiana. Fort Point and Fort Alcatraz in San Francisco Bay, California were also among the forty-two forts. These forts are collectively known as the Third System of Seacoast Defense.
Charleston Harbor made the list of sites vulnerable to attack, prompting the construction of Fort Sumter. Construction on the man-made island began in 1829. Thirty-one years later, sectional tensions exploded at Fort Sumter into armed conflict.
Last updated: March 10, 2019