George Mason IV was born into a prominent Chesapeake region family, with extensive land holdings in both Maryland and Virginia. Mason’s father, also named George, died when young George was a child. His mother, Ann Thomson Mason, took over the responsibility of the family plantations and business interests. Eventually, George and his two siblings (Mary and Thomson) each inherited substantial properties.

When Ann Eilbeck and George IV married, they lived in a house on land inherited by George. They soon decided to build a new, fashionable home for their growing family. They located their new house near the Potomac and called it Gunston Hall.

The Mason family at Gunston Hall took different shapes at different times. Ann and George moved into Gunston Hall with numerous children. With births, deaths, and marriages, the household evolved. It eventually included nieces and nephews, a step-mother, and aunts, as well as adult children and grandchildren. The Mansion overflowed with the nine Mason children who survived childhood, as well as various relatives, and friends.