List of coastal fortifications of the United States

[1] The second system began construction in 1802, due to tensions with Britain and France that ultimately led to the War of 1812.

[4] Although designs varied, most were bastioned polygonal forts, having a large seacoast armament with musketry loopholes and howitzer positions to defend against land attacks.

These forts took decades to build, and many were incomplete when funding was cut off in 1867, especially those begun during the American Civil War.

[8][9][10] In 1885 the Board of Fortifications, chaired by Secretary of War William C. Endicott, met to lay the groundwork for a new coast defense system.

The combination of earth-faced emplacements and disappearing carriages was intended to conceal the guns from an enemy; the airplane had not been invented yet.

Since everything had to be designed and built from the ground up, progress was slow until the Spanish–American War of 1898 potentially threatened the U.S. east coast with bombardment by the Spanish fleet.

In 1917, with World War I in progress and all major powers in possession of dreadnought battleships, the Army decided on a new type of battery.

The initial lack of protection from air attack was a significant problem with these batteries; their only concealment was camouflage and being set back from the coast, although their magazines were in bunkers.

The ports protected by these included Boston, New York City, the entrance to the Chesapeake Bay near Norfolk, Virginia, and Pearl Harbor, Hawaii.

Due to their range advantage over previous weapons, most 16-inch batteries were at new forts, usually called "military reservations" to conceal their purpose.

Due to the diminishing threat of enemy surface attack as World War II progressed, especially on the east coast, of 38 16-inch batteries proposed only 21 were completed, and not all of these were armed.

As the 16-inch batteries were completed the older heavy weapons at the harbor defense commands were scrapped, though some 6-inch and 3-inch guns were retained.