Old forts and batteries on the dunes: Defending the entrance to Charleston Harbor, Part 2

Yesterday I discussed the rather weak defenses on Morris Island, covering the “right” or south end of the Confederate defenses of Charleston Harbor. In the middle, of course, was Fort Sumter an artificial island. To the north lay Sullivan’s Island with old Fort Moultrie sharing the coverage of the main entrance to the harbor.

20th Century view across the channel (Fort Moultrie in the foreground, Fort Sumter in the distance)

When General P.G.T. Beauregard assumed command of the South Carolina, Georgia, and Florida Department, he inherited a project to place a large boom across the main channel between those forts. The boom was composed of railroad iron, banded together, and buoyed by timber. The intent was to produce sort of a floating abatis about four feet under the water. But this plan failed. As result the entire plan to keep the dreaded Yankee ironclads out of the harbor had to be revised.

Beauregard could find comfort in the advanced state of the works on Sullivan’s Island. The center piece, as in April 1861, was Fort Moultrie. In lieu of the complex boom, Confederates set a series of obstructions connected by ropes across the channel. Torpedoes kept also deterred the blockaders. Through the fall and winter of 1862-3, Beauregard pressed Richmond for more large caliber guns. Many of the guns received found positions overlooking the channel.


I discussed Fort Sumter’s armament in March 1863 in the last post. Across the channel, Fort Moultrie contained nine 8-inch columbiads, five 32-pdr rifles, five 32-pdr smoothbores, and two 10-inch mortars. To the right of Fort Moultrie was Battery Bee with five 10-inch columbiads and one 8-inch columbiad. On the other side of Moultrie, Battery (or Fort) Beauregard mounted two 8-inch columbiads, one 32-pdr rifle, and two 32-pdr smoothbores. Combined, these works on the west end of Sullivan’s Island offered a formidable weight of fire against any warships attempting to run up Maffitt’s Channel and into the Main Channel. And at the same time, the guns covered a preferred blockade runner entrance.

1865 view from Fort Moultrie east towards Battery Beauregard

On the map, I’ve included a few works that were conceived but not ready or armed by March 1863. Battery Cove covered the causeway/bridge between the island and the mainland. Batteries Marion and Rutledge were designed to complete the lines between the main works on Sullivan’s Island. At least two “two gun batteries” were started in the center part of the island to complete coverage of Maffitt’s Channel. But these were all “to be” in March and April 1863.

On the far east end of Sullivan’s Island stood a seven gun work simply called “Breach Inlet Battery.” The armament covering that channel included two 32-pdrs, one 24-pdr, four 12-pdrs, and a howitzer. This work later grew into the larger Fort Marshall. Despite the light armament, the battery protected access to the rear of Sullivan’s Island and deterred any attempt to clear the “left” side of the harbor defenses.

Complementing these sea-facing fortifications were a series of supporting works far behind the barrier islands. Although Long Island (today known as Isle of Palms) and Bull’s Bay to the east offered few avenues for Federal advance, the sector did deserve attention.


On the map above, to the left (west) ran the Wando River, and off the map to that side is Charleston. To the bottom (south) was Mount Pleasant and Sullivan’s Island. The major defensive works was a line of posts running across Christ Church Parish, controlling the sparse road network. A couple of additional battery positions covered landing points on the marshes behind Sullivan’s Island. Battery Gary anchored the north end of the bridge leading to Sullivan’s Island. Since Confederates felt no major threat pressing on this sector, these works were largely for infantry pickets. Prepared field artillery positions allowed for reinforcement had the need arose.

The harbor entrance forts and batteries were just part of Charleston’s defensive works. For the next installment, I’ll look at the inner harbor defenses. And in turn look at the land-facing defenses to the north and west. Yes, just as Washington, D.C. and Richmond became fortified cities during the war, Charleston grew it’s share of defenses.

Published by Craig Swain

"Historical marker hunter" and Civil War enthusiast.

9 thoughts on “Old forts and batteries on the dunes: Defending the entrance to Charleston Harbor, Part 2

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