Occoquan is a town in Prince William County in the U.S. state of Virginia. The population was 759 at the 2000 census, but as of the census of 2010, there were 934 people residing in the town of Occoquan. The town is a suburb of Washington, D.C. and is adjacent to Woodbridge. The current mayor is Earnest "Earnie" Porta, who was first elected in 2006, and won re-election in 2008.
Occoquan is derived from an Algonquian Doeg Indian word, meaning "at the end of the water". Located on the Occoquan River, Occoquan was long a site of indigenous peoples' habitation. Like the British colonists after them, they relied on the river for transportation and trade, as well as fish.
By 1765, Anglo-American colonists had established an industrial settlement at Occoquan, with grist mills and tobacco warehouses. The Merchant's Mill was the first automated grist mill in the nation. It operated for 175 years until destroyed by fire.