Kleinostheim is located at the foot of the Spessart in the Lower Franconian district of Aschaffenburg. The place was founded in the 6th century as Ossenheim and first mentioned in a document in 975. Kleinostheim benefits from its proximity to Frankfurt, Offenbach, Hanau and Aschaffenburg as a place of residence for commuters who are gainfully employed in these cities. As a result, the population has doubled from 4.000 to over 8.000 since the 1960s.