Located on private land outside park boundaries on the Gardiner-Mitchell Hill-Jordan Stream Road, Cobblestone Bridge (1917) was the first of 17 bridges constructed along 57 miles of carriage road on Mount Desert Island between 1917 and 1940.

Built with reinforced concrete with battered semi-circular turrets, it has a massive, semi-circular 28-foot arch with rounded cobblestones on both the barrel and spandrel wall. The approaches are widely flared and conform to the layout of the two intersecting roads, and round tower-like buttresses project from the wing walls to provide lookouts both down- and upstream, which allow views of the arch from above. The simple ornamentation consists of roughly articulated granite voussoirs and coping distinguished from the body of the arch. The date of construction, 1917, is carved on the keystone.

It was designed by New York architect William Welles Bosworth, a friend of John D. Rockefeller, Jr. who also designed the main buildings for the Massachusetts Institute of Technology.