Nidau Castle, Medieval castle in Nidau, Switzerland

Nidau Castle is a stone fortress in the town of Nidau and features a central tower with thick walls, complemented by two surviving round defensive towers. The building now houses administrative offices and exhibition spaces dedicated to regional water management history.

A wooden fortification was replaced by a stone castle in the early 13th century, which then served as the residence of the counts of Nidau. This ruling family controlled the castle until 1375, when power shifted in the region.

The castle museum holds an exhibition on the Jura water correction, the 19th-century drainage works that lowered Lake Biel and left the former moat dry. The building also houses the prefecture of the Biel/Bienne administrative district. The name Nidau comes from the counts who ruled here until 1375.

The castle sits directly in the town of Nidau and is easy to reach from outside, but access is limited due to its current use as administrative offices. It is best to check beforehand which areas are open to visitors and when exhibitions are scheduled.

The castle has continuously served administrative functions since its conversion to stone and repeatedly housed the seat of government under different rulers. This continuity makes it a rare example of a fortress that maintained its functional role across centuries.