The Northern Neck is the northernmost of three peninsulas (traditionally called “necks” in Virginia) on the western shore of the Chesapeake Bay in the Commonwealth of Virginia (the other two are the Middle Peninsula and the Virginia Peninsula). This peninsula is bounded by the Potomac River on the north and the Rappahannock River on the south. It encompasses the following Virginia counties: Lancaster, Northumberland, Richmond, and Westmoreland.
The inclusion of King George County in the Northern Neck varies among commentators. Historically, the grant for the Northern Neck included all land between the Rappahannock and Potomac rivers, including far upstream of King George County — some 5 million acres. The boundaries of King George and Westmoreland counties have changed radically since their establishment, with significant exchanges of territory. Significant portions of the early King George County lay in what is now Westmoreland County.