During 1931, Wayne County converted the Michigan Central Railroad's defunct rail bridge crossing the Trenton Channel into the Wayne County Bridge for use by vehicular, bike, and pedestrian traffic.

The rail tracks across the island were replaced by a roadway that is now known as Grosse Ile Parkway.

During much of the 1979 closure period, one lane of traffic remained open on the County Bridge.

At the times when the span was completely closed, the only vehicle access to and from the island was via the Grosse Ile Toll Bridge.

[1] In April 2020, Grosse Ile Township announced that the bridge would be closed for necessary repairs from May 6, 2020, until December 2020.