Fort Dorchester SC: The 1757 Tabby Fort on the Ashley River

Fort Dorchester is a tabby-walled powder magazine built between 1757 and 1760 at the south corner of the colonial town of Dorchester, on the Ashley River in what is now Dorchester County, South Carolina. It was built because the colony feared the French would attack Charleston. The French never came. The British and the Americans did, in turn, twenty years later. The walls are still there, and the state park service calls them the best-preserved tabby fortification in the country.

Why was Fort Dorchester built?

Until 1757, Charleston held the only gunpowder storehouse in colonial South Carolina. That year, with the French and Indian War under way and a French attack on the port considered possible, the legislature authorized a second magazine at a secure inland site. Dorchester was chosen in part because the Ashley River gave it a water route to and from Charleston. A brick magazine went up at the southern edge of the village, and thick tabby walls were raised around it for protection. Sources date the work from 1757 to 1759 or 1760; the state historical marker on the site shows the finished structure as of about 1760.

The structure had no official name while it was in use. People started calling it Fort Dorchester later. The National Register nomination refers to the whole thing, plainly, as a brick powder magazine enclosed by a tabby wall eight feet high.

What is tabby, and why does it last?

Tabby is a concrete made of lime, sand, and oyster shells. The lime came from burning more oyster shells. Mixed with water and poured into wooden forms in layers, it set to something close to the hardness of modern concrete, and the shells stayed visible in the surface. You can still see them studding the walls at Dorchester. The Horn Work in Charleston was built of the same stuff, and so were a number of Lowcountry plantation buildings, but very few tabby forts survive anywhere.

The plan followed European fortification design of the period. The wall was a rectangle around the magazine with half-bastions projecting at each corner, so that defenders standing in a bastion could fire along the face of the adjoining walls. The magazine in the center had its own gun platforms. The whole thing sat on high ground above a bend in the river, defensible from land or water. There is a large gap in one wall today. Nobody knows what caused it.

Fort Dorchester in the Revolutionary War

The French threat passed. The fort sat for fifteen years. Then in the fall of 1775 the Charleston Council of Safety ordered the Dorchester defenses restored, and work on the magazine was finished by October 7 of that year. Colonel William Moultrie ordered 10,000 pounds of powder sent up the river. On November 19, 1775, he sent Captain Francis Marion to Dorchester to guard the cannon, the powder, and the colony’s records. The British attack everyone expected did not come that year. Powder from Dorchester did resupply the Patriots after the Battle of Fort Sullivan in June 1776.

Patriot troops mustered at Dorchester again before the British siege of Charleston in 1780. On March 25, 1780, Hessian troops under Captain Johann Ewald fired on Lieutenant Colonel William Washington’s cavalry near the town and hit one man. Before Charleston fell in May, the Americans removed the powder and supplies. The British then took the post, turned St. George’s Church into a storehouse, and kept a garrison of roughly 150 infantry and 60 mounted troops there. Sources differ on whether the British arrived in April or May 1780.

The garrison left for a time in July 1781, when American cavalry under Wade Hampton and Lee’s Legion threatened Charleston. The end came on December 1, 1781. General Nathanael Greene and Colonel Wade Hampton approached Dorchester. Hampton’s horsemen drove off about fifty South Carolina Loyalists, killing ten and wounding twenty, without a casualty of their own. The British inside, believing Greene had brought his whole army, destroyed what they could, burned the church, threw their guns into the Ashley, and slipped out in the night. They never came back. Charleston was evacuated a year later.

What happened to the fort afterward

After the war the fort became a tile yard, and the magazine was used as a kiln for firing clay roofing tiles. Then it was abandoned along with the town around it. Dorchester never recovered from the war and the fevers, and its people moved to higher, drier ground at what became Summerville, taking the bricks with them. The 1886 Charleston earthquake did further damage to what was left on the site. For a long time the fort’s history was simply forgotten.

The site was listed on the National Register of Historic Places on December 2, 1969, and the state park service has managed it since 1960. Archaeological work continues there. The walls remain. Parts of the magazine remain. Of the whole colonial town, the fort and the brick bell tower of St. George’s Church are the only two structures still standing.

Can you visit Fort Dorchester?

Yes. The fort is inside Colonial Dorchester State Historic Site at 300 State Park Road, Summerville, SC 29485, about 25 miles from Charleston. The park is open daily, 9 a.m. to 6 p.m. during daylight saving time and 9 a.m. to 5 p.m. the rest of the year, closed Christmas Day. Admission is $3 for adults, $1.50 for South Carolina seniors, $1 for children 6 to 15, and free under 6. Phone: 843-873-1740.

Besides the fort you can walk the interpretive trail along the old street grid, see the St. George’s bell tower, the parish cemetery, and at low tide the remains of the log shipping wharves in the river. The park is 325 acres. Dogs are allowed on leash.

The fort is quiet. It was built for a war that never arrived and held through one that did, and it has outlasted the town it was meant to protect. That seems to be the pattern on this stretch of river.

The dispatches from this county keep coming back to Dorchester. The bell tower has its own story in The Tower With No Bell, and the site is marked on the county map. For the longer account of how the town rose and emptied out, see the county history.