Built by the regionally important bridge builders the Groton Bridge Co., this truss is quite important due to several historical and local aspects. As built, this was a pin connected Pennsylvania through truss with a camelback profile, and was completed in 1900. That was also the year which Groton Bridge Co. was absorbed into the American Bridge Co., and would remain there until it separated itself in 1902 and continued on as an independent company. As such this would make it one of the last bridges built by the company before its acquisition, adding to its historical status.
As far as local importance goes, this bridge is one of only a small number remaining of pin-connected bridges in Vermont, and an even smaller amount for remaining Pennsylvania trusses left (and the only example that is a pin connected Pennsylvania truss). The great flood of 1927 wiped out a large amount of early iron and steel bridges, and that along with the inevitable modernization of bridges has made both facets of this bridge a rare commodity both locally and nationally.
In 2002 the bridge had a load bearing arch added through the truss. Unlike some other applications of a load bearing arch though, the arch was not designed to supplement the truss itself and instead completely carries the load. Seemingly highlighting the distinction is the fact that the arch is a dull steel gray, whereas the truss is a standard green.
While a load bearing arch can be a successful way to prolong the life of a historic truss bridge, care should be taken in the decision of when and how to use them. A similar bridge in several respects is the Berlin Iron Bridge Co. Kinderhook Creek Bridge (NBI 3342250), which is an 1899 pin connected Pennsylvania truss that also had an arch added. In that case the arch was designed to supplement the truss, so the original lower chord and floorbeams could be retained. While an arch shouldn’t be a first choice due to how it affects the historic profile of a bridge, when one is needed there are certainly better options for how to integrate it into the existing bridge as to form a compromise with the historic structure and the needs of modern traffic.