The former free imperial city of Giengen an der Brenz is located in the east of Baden-Wuerttemberg on the border with Bavaria, about ten kilometers southeast of Heidenheim an der Brenz and 30 kilometers northeast of Ulm. It is named after the district town of Heidenheim, the second largest town of the district Heidenheim and the fifth largest city in the region East Wuerttemberg. Giengen belongs to the central region Heidenheim, which includes all the municipalities of the district of Heidenheim, and since 1 January 1999 district town.