Hessisch Oldendorf (German ZIP Code: 31840) is located southwest of Hanover in Lower Saxony near the highway Autobahn A2 direction Hannover - Dortmund.
The nearest airport is HAJ / Hannover Langenhagen.
Hessisch Oldendorf can be reached easily by train called Weserbahn, e.g starting from Hanover using the "S-Bahn" in direction Hameln.

Please see also Hessisch Oldendorf in the German Wikipedia