The Back Cove bridge was completed in 1848 when the Atlantic & St. Lawrence Railroad laid track from Portland to Yarmouth. At the time of its construction, the swinging trestle was a marvel of modern engineering.

Later used by the Grand Trunk Railway, the bridge was largely destroyed by fire in 1984. As of 2019, the bridge remains permanently open for tall ships to enter the harbor.

This 1830 subscription form sought subscribers to commit cash, labor or materials to build a bridge connecting the Portland peninsula to the main land.