Oatlands was formed in 1798 from 3,408 acres of prime Loudoun County, Va., farmland by a young bachelor named George Carter, descendant of one of Virginia's first families. Basing his plantation economy on wheat production, Carter eventually branched out to grow other small grains; raise sheep for their wool; develop a vineyard; and build a mill complex on nearby Goose Creek for the grinding of grain, milling of timber, and pressing of flax seed to produce oil cake. In 1801 he began calling his plantation "Oatlands."
In 1804 Carter began building a classic Federal-style mansion near the southern boundary of his property. As his farm took hold and his financial position strengthened, he added a terraced garden and numerous outbuildings to the property, including a propagation greenhouse, a smokehouse, and a three-story bank barn. During the 1820s and 1830s Carter added to and embellished his mansion.