Once home to more than a dozen stone arch masonry bridges, Hillsborough now has five of these gems, four of which are used everyday to support auto, bike and foot traffic.
These bridges are registered as historic structures by the Historic American Building Survey, part of the National Park Service. Most recently they have been recognized as a National Historic Civil Engineering Landmark, the second in New Hampshire, after the Cog Railway.
http://www.hillsboroughnhchamber.com/bridges.html