Photo by NCinDC.

The Castle Gatehouse is one of those mysterious buildings that few know about and those that do wonder about. How curious, a castle-like building on the Georgetown Reservoir, near the Capital Crescent Trail.

Unfortunately, this building’s history doesn’t quite live up to the intrigue. The Castle Gatehouse was built between 1899 and 1901 by the Army Corps of Engineers, as a pump station. Yes, the castle pumps water into the four-mile long Washington City Tunnel that leads to the McMillan Reservoir.

Why a castle for a pump station? The Army Corps built it as so to resemble the Army Corps of Engineers insignia. The origin of the insignia is unclear. Unfortunately, the official records of the Corps, including those that contained the reason behind the insignia, were destroyed in a fire in 1838 at West Point. For the Castle Gatehouse, they used Portland cement plaster to replicate stonework and give the gatehouse an authentic castle appearance.

The Castle Gatehouse resides in the Palisades neighborhood off of MacArthur Boulevard and Reservoir Road. The Army Corps of Engineers still runs the fancy pump station.