The Northern Neck Proprietary — also called the Northern Neck land grant, Fairfax Proprietary, or Fairfax Grant — was a land grant first contrived by the exiled English King Charles II in 1649 and encompassing all the lands bounded by the Potomac and Rappahannock Rivers in colonial Virginia. This constituted up to 5,000,000 acres (20,000 km2) of Virginia's Northern Neck and a vast area northwest of it.