Plantations that operated within the present-day boundaries of West Virginia were located in the counties of the Ridge-and-Valley Appalachians and in the Kanawha and Ohio River valley regions. Beginning in the mid-to-late 18th century, members of the Washington family and other prominent Virginia families began to build elegant Georgian mansions on their plantations in the Ridge-and-Valley Appalachians region of present-day West Virginia. Plantations initially developed in the counties lying within the Northern Neck Proprietary of Thomas Fairfax, 6th Lord Fairfax of Cameron within the Shenandoah Valley and South Branch Potomac River valleys. Slavery as practiced through plantations in the American South was carried over from the plantations of the Piedmont and Tidewater regions of Virginia