The Tromøy Bridge is a suspension bridge that crosses the Tromøysundet strait in the municipality of Arendal in Agder county, Norway. It connects the island of Tromøya with the mainland, about 3.5 km northeast of the town of Arendal. The bridge is part of Norwegian County Road 409 and it opened on 21 October 1961 by Trygve Bratteli, the Minister of Transport and Communications. The bridge originally cost NOK7 million. The 400 m long bridge has 12 spans, the longest of which is 240 m. The bridge has a 37 m high clearance underneath it so ships may pass under it. In 2008, the annual average daily traffic was 8,350 cars per day. Its building was prepared by a special committee which was chaired by Christian Stray during its entire existence from 1938 to 1961.