The west of Aalen's territory is on the foreland of the eastern Swabian Jura, and the north and north-west is on the Swabian-Franconian Forest, both being part of the Swabian Keuper-Lias Plains. The south-west is part of the Albuch, the east is part of the Härtsfeld, these two both being parts of the Swabian Jura.