In 1798 a young bachelor named George Carter inherited 3,408 acres of prime Loudoun County, Virginia farmland. Carter was a descendant of one of Virginia’s first families. Oatlands based its plantation economy on wheat production, and eventually Carter branched out to grow other small grains; raise sheep for their wool; and build a mill complex on nearby Goose Creek. The success of Oatlands depended upon a slave economy; by 1860, the enslaved community at Oatlands numbered 133 men, women, and children.
In 1903 prominent Washingtonians, William Corcoran Eustis, and his wife Edith Morton Eustis purchased Oatlands as their country home. William was a grandson of Washington philanthropist William Wilson Corcoran, and Edith was the eldest daughter of Vice President Levi P. Morton. Following Edith's passing in 1964, the family donated the property to the National Trust for Historic Preservation in 1965. Oatlands is a National Historic Landmark, the highest designation given by the National Park Service.