Schloss Drachenburg or Drachenburg Castle is a private villa styled as a palace and constructed in the late 19th century. It was completed in only two years (1882–84) on the Drachenfels hill in Königswinter, a German town on the east bank of the Rhine, south of the city of Bonn. Baron Stephan von Sarter [de] (1833–1902), a broker and banker, planned to live there but never did.
The villa is owned by the State Foundation of North Rhine-Westphalia. It is served by an intermediate station on the Drachenfels Railway.
In 1963, a Syndicate for the Preservation of Drachenburg was founded which succeeded in getting the castle classified as worth preserving. It was purchased, in 1971, by a local textile merchant, Paul Spinat, who carried out major restorations and used it for entertaining and also opened for visitors. He died in debt in 1989 and the State of North-Rhine, Westphalia took over the estate and carried out a further series of restoration works stretching over 20 years.
The restoration was greatly helped by the existence of a number of postcards and other illustrations commissioned by Jacob Biesenbach for his original tourism project at the beginning of the 20th century. The building is now administered by the North-Rhine, Westphalia Foundation.