Trachselwald District is a district in the canton of Bern, Switzerland. From 1 January 2010, the district lost its administrative power while being replaced by the Emmental, whose administrative centre is Langnau im Emmental. Since 2010, it remains therefore a fully recognised district under the law and the Constitution of the Canton of Berne. Its governor's seat was in Trachselwald Castle in Trachselwald. It consistes of 10 municipalities within an area of 191 km².