Nidau Castle and the Jura Water Regulations

19 April 2026

The Count of Neuenburg zu Nidau built the moated castle around 1140; it was first mentioned in documents in 1196. In the Middle Ages, the water level of Lake Biel was 2 metres higher, and the castle stood directly on the lake’s shore. The castle rose up into the sky as an imposing and difficult-to-conquer fortress.

The Counts of Nidau, officially known as the ‘Counts of Neuenburg, Lords of Nidau’, played an important role in the region until 1375 (the Gugler War). The last Count of Nidau, Rudolf IV, was killed in 1375 in the battle against the Guglers.

The Guglers were mercenaries who migrated to the Swiss Mittelland during the Hundred Years’ War (1337–1453) between the kingdoms of France and England.

The city of Bern (and Solothurn) organised the resistance, and in 1376 the Guglers withdrew once more. The castle then passed to the Bishop of Basel and, after him, to the Count of Neu-Kyburg. Bern (and Solothurn) captured the castle and the town in 1388.

Richard La Nicca (1794–1883)

Following the conquest, the castle served as the seat of the bailiff of Bern. In the 19th century, the southern section of the curtain wall was demolished and the moats filled in. This was made possible by the Jura Water Correction (1868–1891), which lowered the water level of Lake Biel by 2 metres.

Due to its location at the mouth of the (Alte) Zihl (Thielle in French) and its status as a border town with the Prince-Bishopric of Basel, Nidau served as an important customs post until the early 19th century. Today, the administrative district of Biel (Bienne) is headquartered at Nidau Castle.

(Quelle and further information: Schlossmuseum Nidau)

The tower of Nidau