Robert Carter III was an American planter and politician from the Northern Neck of Virginia. During the colonial period, he sat on the Virginia Governor's Council for roughly two decades. After the American Revolutionary War saw the Thirteen Colonies gain independence from the British Empire as the United States, Carter, influenced by his belief in Baptism, began the largest manumission in the history of the United States prior to the American Civil War.

The Northern Neck is the northernmost of three peninsulas on the western shore of the Chesapeake Bay in the Commonwealth of Virginia(along with the Middle Peninsula and the Virginia Peninsula). The Potomac River forms the northern boundary of the peninsula; the Rappahannock River demarcates it on the south. The land between these rivers was formed into Northumberland County in 1648, prior to the creation of Westmoreland County and Lancaster County.