Hemlock Bridge (1924) was the fourth of 17 bridges constructed along 57 miles of carriage road on Mount Desert Island between 1917 and 1940. It carries the Jordan-Sargent Mountain Road over a deep, rocky ravine created by the Maple Spring Brook. The difficult, yet spectacular site conditions necessitated careful ground inspection and preliminary staking to ensure that the site was not adversely affected by construction.

The massive 200-foot curved bridge is made of reinforced concrete clad with quarried granite ashlar. A main Gothic arch, which spans 37 feet and measures 35 feet at its highest point, has a ring of radiating granite voissoirs that
increase in size from keystone to springline. It is flanked on either side by smaller blind arches and curved parapets that highlight the dramatic topography and follow the curve of the roadway to spiraled end posts.

The final cost was $58,619.80 when completed in 1924.