The decision was made to extend I-95 north from the New Hampshire Turnpike at Portsmouth and south from the Maine Turnpike in Kittery, and join the roads with an uninterrupted high speed span over the Piscataqua. Work on the bridge was completed in 1971, and the I-95 extension to it in Maine was completed the following year. The bridge was designed by the engineering firm Hardesty & Hanover and constructed by Cianbro Corp.
Tragedy struck the site about midway through construction. On June 24, 1970, two of the I-beams supporting the staging area on the Kittery side of the span gave way, sending four workers 75 feet down to their death and leaving another seven injured.