Castle Saarbrücken in Saarbrücken in the state of Saarland. The Castle is a baroque castle in the Alt-Saarbrücken part of the city. In the past there were a fortress and a renaissance castle on site. Today it is the seat of the district government Saarbrücken. In the cellar and an extension building is the History Museum Saar. Under the adjacent square there are excavations of the historic fortress