Oberndorf belonged to the Prince-Archbishopric of Bremen, established in 1180. In 1648 the Prince-Archbishopric was transformed into the Duchy of Bremen, which was first ruled in personal union by the Swedish Crown - interrupted by a Danish occupation (1712–1715) - and from 1715 on by the Hanoverian Crown. The Kingdom of Hanover incorporated the Duchy in a real union and the Ducal territory became part of the new Stade Region, established in 1823.