Colonial Dorchester State Historic Site, State historic park in Dorchester County, US.

Colonial Dorchester State Historic Site is a 325-acre South Carolina state park on a neck of land between the Ashley River and Dorchester Creek, near Summerville. Its centrepiece is St. George's Bell Tower, a brick tower split by the 1886 earthquake and repaired in the early 1960s, standing beside the tabby walls of a fort and powder magazine built from 1757 to 1760, with oyster-shell tabby foundations, log wharf remains and burial grounds among the trees.

In January 1696 a group from Dorchester, Massachusetts, bought 4,050 acres here, and Reverend Joseph Lord preached his first sermon that month. The town peaked in the mid-1700s as a river port for rice, indigo and trade with Native Americans, with a fair from 1723 and a Free School from 1734. British troops burned St. George's Church and were driven out in December 1781; the site was abandoned and donated to the state park service in 1969.

St. George's Anglican Church was completed in 1719 and its bell tower added in 1751; the tower survived because scavengers feared it would fall on them, as an 1858 magazine noted. The 1886 Charleston earthquake split the tower, which was held together with iron straps until repairs in the early 1960s.

The 325-acre site is entered on foot from the parking area off State Road S-18-373, and the ruins, fort and riverbank are linked by paths across open ground. The tabby fort and the bell tower stand at the centre of the former town grid, with the Ashley River and Dorchester Creek on either side. Much of the ground is unshaded, and archaeological digs continue in places.

The fort walls were built from tabby, an early building material made by burning and crushing oyster shells to create a rough form of concrete. The shells came from the same river environment that surrounded the town, so the builders essentially used the landscape itself as a source of raw material.