city, Schleswig-Holstein Land (state), Germany. A port at the head of Flensburg Fjord, it is Germany's most northerly large city. First mentioned in 1240, it was chartered in 1284 and was frequently pillaged by the Swedes after 1643. It became the capital of Schleswig under Danish rule in 1848 and was occupied by Prussia after the German-Danish War of 1864. In the plebiscite held in 1920, Flensburg voted to remain in Germany. The site of a naval station and academy before World War II, it again became a naval base after the establishment of West Germany.
Learn more about Flensburg with a free trial on Britannica.com.