The bridge's entire construction cost was $32 million. It consisted of a main span of 1,752 feet (541 m) and 23 approach spans ranging in length from 100 to 330 feet (30 to 100 m). The main span is the longest continuous truss span in the world. It crosses Dauphin Island Mote on its way from Mobile to Bay Saint Louis. The main body of the bridge is made up of 2,722 transverse members and 156 vertical posts. Each transverse member is composed of two Y-shaped girders with their free ends connected by a horizontal crosspiece. The whole assembly is then tied together with wire cables attached to each side of the frame. There are also several smaller girders inside the main one; these are used as floor beams or as part of the railing system. The bridge was built by the Meyer, Nunn & Myers company in Pittsburgh. The foundation for the main span was poured on October 3, 1955, and the main span was completed three years later on February 21, 1958. The project was managed by the United States Army Corps of Engineers.