Northern Neck Proprietary in the context of "North Branch Potomac River"

Colonel Thomas Lee (c. 1690 – November 14, 1750) was a planter and politician in colonial Virginia, and a member of the Lee family, a political dynasty. Lee became involved in politics in 1710, serving in both houses of the Virginia General Assembly, and also held important positions as Naval Officer for the Northern Potomac Region and agent for the Northern Neck Proprietary. After his father died, Lee inherited thousands of acres of land as well as enslaved people in then-vast Northumberland and Stafford Counties in Virginia as well as across the Potomac River in Charles County, Maryland. These properties were developed as tobacco plantations. Northumberland County was later subdivided, so some of Lee's properties were in present-day Fairfax, Fauquier, Prince William, and Loudoun counties and counties in the present-day Northern Neck of Virginia.

When Lee married Hannah Harrison Ludwell in 1722, he benefited from the connections of the already established Harrison family of Virginia. A year later, he would become a member of the House of Burgesses. Arson destroyed Lee's home, he used money from Caroline of Ansbach and Britain to build Stratford Hall overlooking the Potomac River. Four years later, in 1733, he was appointed to the Governor's Council, the upper house of the General Assembly. In 1747, he founded the Ohio Company of Virginia with fellow Virginian colonists who wished to expand Virginia's territory into the Ohio River Valley. For less than a year, in 1749 until his death in 1750, Lee served as the de facto royal governor of Virginia in place of the absent William Gooch.