Groß-Gerau lies in the north of the Hessisches Ried, the northeastern section of the Rhine rift.

Already by Roman times, the area forming today's town of Groß-Gerau had great importance.

Federal Highway (Bundesstraße) B44 from the southern tip of the old pheasantry (at Auf Esch) to Dornheim corresponds exactly with the old Roman road from Mainz through Groß-Gerau to Ladenburg.

The fact that this vicus and the later mentioned Wasserburg Dornberg (moat-ringed castle) corresponded very closely in location would be no accident.

The Gerauer Mark (Gerau March, the woods between Wallerstädten and Messel) had its first documentary mention in one of Mainz Archbishop Hatto I's donation documents in 910.

Landgrave Ludwig VI of Hesse-Darmstadt renewed Groß-Gerau's town rights in 1663 for a payment of 24000 Gulden.

The town became headquarters to metalworking businesses (FAGRO), canneries (Helvetia), cheesemakers (Groß-Gerau is where "Mainz" cheese is made) and the sugar industry.

A plan to connect two local railway stations and the surrounding communities together with a tramway in the late 19th century fell through, and there are still no trams in the town even now.

Relatively high debt loads and strict controls of public institutions (especially at the district level) by the government presidium in Darmstadt have led to this.

(Each time as at 31 December) Groß-Gerau's council is made up of 33 councillors, with seats apportioned thus, in accordance with municipal elections held on 6 March 2016: (in parentheses changes from municipal elections held in March 2011): Note: KOMBI is a citizens' coalition.