Boosenburg, Medieval castle in Rüdesheim am Rhein, Germany.

The Boosenburg is a lowland castle on the right bank of the Rhine in Rüdesheim am Rhein, known locally as Oberburg because it sits slightly above the neighbouring Brömserburg. Its very tall, double-stepped bergfried rises from a cubic building that once held the entrance, and the complex was secured by a ring wall and a nine-metre-wide moat. In the late Middle Ages additional living quarters were added.

The castle was built in the 12th century as a residence for the Fuchs family of Rüdesheim. In 1407, it passed to the Brömser von Rüdesheim family, one of the most influential noble families in the region at that time.

The castle has housed the Carl Jung winery since 1938. Carl's son Hans Otto Jung, a founding member of the Hotclub Combo in the 1940s, played jazz here with notable musicians on two Steinway pianos. His son Edu Jung later opened the venue to concerts of the Volkshochschule.

The tower is not open to visitors, but the outer walls and the overall shape of the castle can be seen and photographed from the street. It sits in the center of Rüdesheim am Rhein and is easy to reach on foot from other points of interest in town.

The old moat around the castle was converted into a vaulted wine cellar that is still in use today. This transformation turned what was once a defensive feature into one of the most practical parts of a working winery.