Sixth Corps Area was a Corps area, effectively a military district, of the United States Army from 1921 to the 1940s. The headquarters was established at Fort Sheridan, Illinois, in August 1920, from portions of the former Central Department, but then moved to the U.S. Post Office Building at 1819 West Pershing Road in Chicago on 10 October 1921.
It covered the states of Wisconsin, Michigan and Illinois and Jefferson Barracks, Missouri. It was responsible for the mobilization, administration, and training of units of the Second and Fifth Armies, I Cavalry Corps (Regular Army, but inactive, 1927-1940), VI Army Corps (including the Regular Army 6th Division, 32d and 33rd Divisions) and XVI Army Corps (85th, 86th, 101st Divisions), select GHQ Reserve units, and the Zone of the Interior support units of the Sixth Corps Area Support Command.
Paul Malone was promoted to Major General and assumed command of the Sixth Corps Area in Chicago in 1928. Malone then left the United States in April 1929 and embarked for the Philippines, where he assumed command of the Philippine Division at Fort William McKinley.
Major active-duty installations in the corps area included Fort Brady, Chanute Field, Camp Custer, Jefferson Barracks; Scott Field, Fort Sheridan, and Fort Wayne.Camp Douglas and Camp Grant were among the National Guard installations.