Darmstadt-Dieburg is a Kreis in the south of Hesse, Germany. Neighboring districts are Offenbach, Aschaffenburg, Miltenberg, Odenwaldkreis, Bergstraße, Groß-Gerau, and the district-free city of Darmstadt, which it surrounds.
Wikipedia https://en.wikipedia.org/wiki/Darmstadt-Dieburg
Coordinates 49°52'21.99" N 8°39'4.237" E