Stadtallendorf borders in the north on the town of Rauschenberg (Marburg-Biedenkopf) and the community of Gilserberg (Schwalm-Eder-Kreis), in the east on the town of Neustadt, in the southeast on the town of Kirtorf, in the south on the town of Homberg (Ohm) (both in the Vogelsbergkreis), and in the west on the towns of Amöneburg and Kirchhain (both in Marburg-Biedenkopf).