Constructed in 1832 from locally quarried gleaming red sandstone, the triple-arched Seneca Aqueduct was the first of eleven such structures built to carry the C&O Canal across tributaries of the Potomac River. It was also the only aqueduct designed with a canal lock (Lock 24) integrated into it. Together with a matching red sandstone lockhouse manned by longtime lockkeeper John Riley, the entire collection gains attention for its unique layout and color. Seneca Aqueduct was damaged when floodwaters from Seneca Creek rose in 1971, and the westernmost arch has been supplanted by steel beams.
Open dawn to dusk. Parking is available on site next to the lockhouse at Lock 24.