Originally spanning Big Pipe Creek in Detour, Carroll County, Maryland, this Bowstring Arch Bridge, circa 1872, was later reduced in width and moved to its present site over Little Hunting Creek. Patented in the early 1840s by the internationally known inventor Squire Whipple, this truss bridge was important to the industry and economics of young America. Borrowing its form from earlier wooden structures, the double iron design was less susceptible to damage and wear from the elements. These prefabricated bridges were erected across rural America, and many still span waterways. Truss bridges depend on compression and tension to support the forces of gravity: the arch itself is under compression and tends to be pushed together by forces acting on it, while the thinner diagonal and vertical braces are subject to tension and help support the deck and arch of the bridge.