In the course of the monastery’s being raised to Imperial Abbey, answerable only to the Pope, and no longer within the grasp of the bishoprics of Mainz and Worms, the Emperor donated to the monastery the domain of Heppenheim in 773, which comprised the greater part of today’s Bergstraße district and great parts of the Odenwaldkreis.
Grasellenbach borders in the north on the community of Fürth, in the east on the community of Mossautal (Odenwaldkreis), in the south on the community of Wald-Michelbach and in the west on the community of Rimbach.
Bordering on Mömlingen are the Bavarian district of Aschaffenburg in the north, and in the west the two Hessian districts of Darmstadt-Dieburg and Odenwaldkreis.