Discover a part of Northern Virginia’s industrial heritage — the restored gristmill at Aldie Mill Historic Park, in Aldie. Built between 1807 and 1809, the Aldie Gristmill was once the largest factory of its kind in Loudoun County. The mill’s tandem metal waterwheels are fully operational, making it possible for visitors to watch live grinding demonstrations. Aldie Mill is available to rent for events and meetings. Tours and demonstrations are available during weekends between April and November.