Westover Plantation is located on the north bank of the James River in Charles City County, Virginia. It is located on State Route 5, a scenic byway which runs between the independent cities of Richmond and Williamsburg. It is a US National Historic Landmark. Westover Plantation was formerly claimed to have been built circa 1730 by William Byrd II, the founder of Richmond; this date appears in the 1960 designation of the house as a National Historic Landmark. However, recent dendrochronologic testing on boards and planks in the house shows that they actually date to the 1750s, and this is the date of construction now recognized by the National Park Service. Therefore the house was probably built by William Byrd III, not his father William Byrd II. The house is noteworthy for its secret passages, magnificent gardens, and architectural details. The grounds and garden are open 9 a.m. to 6 p.m. daily, but the house is not open to the public.