city, Schleswig-Holstein Land (state), northern Germany. It lies on the Elbe River Estuary, northwest of Hamburg. It was founded in 1616 by Christian IV of Denmark to rival Hamburg as a trading port. The fortress was demolished in 1815–16, but the extensive marketplace and many old buildings remain. The palace (built in 1631–32) houses a museum of local history, handicrafts, navigation, and whaling. The renovation of the town's historic city centre has won regional and national awards for historic preservation. Glückstadt is an important training ground and garrison for the German military. Once a prominent centre for herring fishing, the town hosts an annual herring festival. Glückstadt has a major trade in vegetables, especially new potatoes. Pop. (1999 est.) 12,352.