Elbmarsch (Northern Low Saxon: Elvmasch) is a Samtgemeinde ("collective municipality") in the district of Harburg, in Lower Saxony, Germany. It is situated on the southern (left) bank of the river Elbe, approx. 30 km southeast of Hamburg, and 20 km north of Lüneburg. Its seat is in the village Marschacht. The name refers to the marshes (German: Marsch) along the Elbe.
The Samtgemeinde Elbmarsch consists of the following municipalities: