At Aldie Mill Historic Park, you’ll discover a part of Northern Virginia’s industrial heritage. 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. Tours and demonstrations are available during weekends between April and November. And if you enjoy living history, be sure to check out the programs at nearby Sky Meadows State Park.