Ornbau is a walled town in the district of Ansbach, in Bavaria, Germany. It is situated on the river Altmühl, 15 km southeast of Ansbach. Ornba…Ornbau is a walled town in the district of Ansbach, in Bavaria, Germany. It is situated on the river Altmühl, 15 km southeast of Ansbach. Ornbau is the smallest town in the German state of Bavaria. Its designation as a town dates back to medieval times because a wall and a moat surround the town.