Hessisch Oldendorf is a town in the Hamelin-Pyrmont district, in Lower Saxony, Germany. It is situated on the river Weser, approx. 10 km northwest of Hamelin. The adjective "Hessisch" is used since 1905, to distinguish it from other towns named Oldendorf. Hessisch Oldendorf was part of Landgraviate of Hessen-Kassel from 1640 until 1932.