CABIN JOHN BRIDGE
Erected about 1860 by Gen. Montgomery G. Meigs, this bridge spans Cabin John Run, about 7 miles northwest of Washington. It is a part of the aqueduct system, and the arch spanning the stream is 220 feet across at the base and 105 feet in height. The entire length of the bridge is 584 feet. The thickness of the bridge above the arch is 14¹⁄₂ feet, and it is 20 feet in width. Until a few years ago it was the largest stone arch in the world.