An S bridge is a double-curved bridge, shaped roughly like a shallow letter S, used in early 19th century road construction in the United States. They were generally used for crossing small, curving streams with uneven banks. These bridges are found in and around the New Concord, Ohio area.
S bridges were originally constructed early in the 19th century. The design was adopted where the road crossed the creek or river at an angle. Constructing a bridge at an angle was much more complicated and expensive than building the bridge perpendicular to the water flow and banks. The bridges were constructed at 90 degrees to the bank, while two 'aprons' were constructed at opposite angles to direct the traffic flow smoothly onto the bridge, thus creating the 's' shape.[1][2]
Only a few of these bridges still exist, mostly in Ohio. Four of them are located in Guernsey County, two of which are still in use carrying traffic. Fox Run S bridge is located along US Route 40 in New Concord in Muskingum County. The next bridge, four and a half miles east from New Concord on US Route 40, is found at the intersection of US 40 and Peter's Creek Road. Continuing eastward, the next bridge may be found a short distance from US 40 on Manilla Road; this bridge is still in use but may not be noticeable as it has been paved over and has had guardrails added to it. The next "S" bridge is 1.5 miles east of Cambridge along US 40 at its intersection with Old National Road and has fallen into considerable disrepair. The fourth bridge is located between Old Washington, Ohio and Middlebourne, Ohio along Bridgewater Road, at the intersection of Blend Road, and has been designated a National Historic Landmark. This bridge is still accessible to local traffic.
These four bridges were constructed as a part of the original National Road, which was built circa 1825.
The Claysville S Bridge, in Washington County, Pennsylvania, is listed on the National Register of Historic Places. Another S bridge, in Anderson County, Kentucky, is located on US Route 62 east of Lawrenceburg. It has undergone major roadway replacement and has been widened. There is a plaque at the east end of the bridge that reads as follows:
Jo Blackburn Bridge. Dedicated to the memory of Joseph Clay Styles Blackburn, 1838-1918. Confederate Soldier, Congressman, United States Senator, Governor of the Panama Canal Zone. Built by the State Highway Commission of Kentucky 1932. Capacity 15 ton trucks.
Another S bridge of note is located in Hertford, North Carolina. It connects a causeway from Winfall to the Town of Hertford, over the Perquimans River.