Old castle Bümpliz, Medieval castle in Bümpliz village, Switzerland.

Old castle Bümpliz is a fortress with a square gatehouse tower, stone walls, and several wings arranged around an inner courtyard. The structure displays typical medieval castle architecture and sits in the southwestern part of Bern.

The fortress originated around 900 as a royal Burgundian estate when the region was under that kingdom's control. Stone fortifications replaced the original wooden structures during the 13th century, marking a shift toward permanent defensive architecture.

The castle served as the residence of the von Erlach family, a powerful local aristocratic clan whose influence shaped the Bern region. Today visitors can observe how the layout and rooms reflect the social hierarchy and authority of this family.

The restaurant occupies the north-east wing, the gatehouse and the courtyard; the gate in the gatehouse tower was reopened in 1979/80 and part of the moat was excavated with a drawbridge added. The spot of the vanished round tower is marked by a cross on the restaurant terrace floor. The castle also houses the Bümpliz local archive and serves as a rehearsal room for the Bern Conservatory.

In 1839 the castle was converted into a mental health facility where patients were separated based on their condition. Calmer patients stayed in the newer portion of the complex while those requiring more intensive care occupied the older structures.