迪特马尔申县（Kreis Dithmarschen）是德国石勒苏益格-荷尔斯泰因州西部的一个县，位于汉堡和北弗里斯兰县之间，临北海、易北河、埃德河（Eider）和北海-波罗的海运河，首府海德。

Dithmarschen (German pronunciation:[ˈdɪtmaʁʃən], Low Saxon pronunciation: [ˈdɪtmaːʃn̩], archaic in English: Ditmarsh, Danish: Ditmarsken, Middle Latin: Tedmarsgo) is a district in Schleswig-Holstein, Germany. It is bounded by (from the north and clockwise) the districts of Nordfriesland, Schleswig-Flensburg, Rendsburg-Eckernförde, and Steinburg, by the state of Lower Saxony (district of Stade, from which it is separated by the Elbe river), and by the North Sea.