It is situated on the south side of the Flensburg Fjord, an inlet of the Baltic Sea, approx. 10 km northeast of Flensburg. The town was originally the home of the family Schleswig-Holstein-Sonderburg-Glücksburg (or simply Glücksburg), since 1863 the royal family of Denmark and since 1905 of Norway. A branch of the family was the former royal family of Greece, which includes Prince Philip, Duke of Edinburgh and therefore includes the lineage of the current monarchy of the Commonwealth Realms.
Glücksburg is home to a German Navy base. Among the facilities at the base is the transmitter, callsign DHJ58. DHJ58, situated at 54° 50'N and 9° 32' E, ceased its transmissions on longwave frequency 68.9 kHz in 2002 and in 2004 its longwave antenna was disassembled.
Chisholm, Hugh, ed. (1911). "Glücksburg". Encyclopædia Britannica (11th ed.). Cambridge University Press.