Bundesautobahn23 (translates from German as Federal Motorway23, short form Autobahn23, abbreviated as BAB23 or A23) is an autobahn in Germany. It runs largely parallel to the Bundesstraße 5; its main purpose is to connect the hinterland of Hamburg. North of Heide, the A23 becomes B5 and connects Eiderstedt, Husum and the ferries to the islands of Nordfriesland to the autobahn network.