Photographs of the Bridges
Cabin John Bridge, near Glen Echo, Maryland
The Cabin John Bridge, also known as Union Arch, is only a traffic bridge in its outward appearance. The arch was actually constructed as part of the 18.6 mile-long Washington Aqueduct, a conduit designed to provide a stable water supply for the growing Federal City of Washington, DC. The aqueduct, which is still in operation more than 170 years later, intakes fresh water from the Potomac River above Great Falls, and transports it into the central part of the city.
Construction on the arch began in 1853, but then was interrupted by the beginning of the Civil War. Construction resumed, and the structure was completed in 1863. The bridge does not carry a normal pipeline, but encloses a nine foot-diameter, brick-lined conduit for the transport of the water. At the time it was constructed, it was the longest single-span stone bridge in the world, at 220 feet long, and the center of the arch is eighty feet high above Cabin John Creek.
This enormous size resulted in the completed bridge becoming one of the most prominent tourist sites in the area in the late nineteenth century. By 1896, the Foundry Branch Trolley Line, parallel to Conduit Road (now MacArthur Boulevard), had connected Georgetown to the amusement park at Glen Echo, and then continued north to the southern end of the famous bridge and, one the opposite end of the bridge, the grand Cabin John Bridge Hotel. The hotel operated until the 1920s, when Prohibition caused a decline. The hotel closed in 1926, and then burned in 1931, still packed with antiques, china, and silver from its better days.
The bridge does carry a roadway, consisting of a single lane of MacArthur Boulevard, as well as a sidewalk that is part of a regional hike and biking trail. The bridge can be accessed, on foot or bicycle, by the asphalt trail that parallels MacArthur Boulevard and crosses the bridge. Cabin John Local Park is just off of the northern end of the bridge, and has ample parking a short distance away.
Although the bridge is in Maryland a few miles outside of the District of Columbia boundary, I included it in my new book, Bridges of Washington, DC: A History and Guide, because it is a prominent local landmark.
