Oatlands Historic House and Gardens (formerly Oatlands Plantation) is an estate located in Leesburg, Virginia. Oatlands is operated by the National Trust for Historic Preservation and is listed on the National Register of Historic Places as a National Historic Landmark. The Oatlands property is composed of the main mansion and 415 acres (168.0 ha) of farmland and gardens. The house is judged one of the finest Federal period country estate houses in the nation.