Rethem (German pronunciation: [ˈʁeːtəm]) is a town in the Heidekreis in Lower Saxony, Germany. It is situated on the river Aller, approx. 25 km southwest of Bad Fallingbostel, and 18 km southeast of Verden. The town was the scene of heavy fighting over the period 10–11 April 1945 between units of the British 53rd Welsh Division and parts of the German 2. Marine-Infanterie-Division with heavy losses on both sides.