The Thetford Center Covered Bridge is located a short way west of the village of Thetford Center, spanning the south-flowing Ompompanoosuc River, a tributary of the Connecticut River. The bridge has a span of 128.5 feet (39.2 m), and rests on dry laid stone abutments that have been capped in concrete and a central concrete pier. The bridge is covered by a metal roof and sheathed in vertical board siding. The portal ends project beyond the deck by about 1 foot (0.30 m). The deck is now supported by steel I-beams, and the original bridge trusses support only the bridge superstructure. The bridge has a total width of 20.5 feet (6.2 m), with an 18-foot (5.5 m) wide roadway (one lane). The bridge trusses are a variant of a multiple kingpost truss. Each truss has verticals and diagonals in that style, but is further augmented by a laminated arch, consisting of heavy planks pegged together.[2]
The bridge's construction date is unknown. It is the only example of the Haupt patent truss known in the state, and may be the only example in the northeastern United States. The alterations made to support the deck with I-beams, including capping the abutments and adding the central pier, were made in 1963.[2]
