IX Army Corps (IX. Armeekorps) was a corps in the German Army during World War II. It was formed on 1 October 1934 under the command of General Friedrich Dollman in Kassel with the camouflage name of Kassel and redesignated IX Corps after the creation of the Wehrkreis IX recruitment and training area. After the general mobilisation in August, 1939 IX Corps were stationed near Worms as 1st Army reserves. In May 1940 they took part in Fall Gelb, the Manstein plan to invade the Low Countries and France via the Ardennes, pushing on to Dunkirk.