Trachselwald Castle is a castle in the municipality of Trachselwald in the canton of Bern, Switzerland. It is a Swiss heritage site of national significance.HistoryThe name of the rulers of the castle was first mentioned in 1131. The castle itself may date back to the 10th century but the 11th or 12th century is more likely. At first it belonged to the barons of Trachselwald, then to the barons of Rüti bei Lyssach, and then those of Sumiswald. The barons of Sumiswald sold the castle and surrounding lands to the city of Bern. Bern turned the castle into a sheriffhood.The castle was rebuilt or expanded several times. Its oldest parts are the keep, which was built out of tuff, and one half of the main building. These parts of the castle were built in the second half of the 12th century. The stair tower was probably built by a master craftsman from Prismell in 1641.During the Swiss peasant war of 1653, the peasant leader Niklaus Leuenberger, who was arrested on June 19, 1653 was held in Castle Trachselwald until being taken to Bern, where he was executed on August 27.