The headquarters was activated about 24 October 1921 with Regular Army and Organized Reserve personnel at the Custom House Tower in Boston, Massachusetts.

The headquarters was relieved from active duty in 1925 and all Regular Army personnel were reassigned to the Headquarters, Non-Divisional Group, First Corps Area, which assumed the responsibilities previously held by the XI Corps.

The XI Corps was not activated prior to World War II, and was located in Boston as of 7 December 1941 in a reserve status.

[5] XI Corps embarked for the South West Pacific Area in March 1944 and was assigned to the Alamo Force after arriving at Finschhafen, New Guinea.

[5] A unit history named Paradise Parade was published by the XI Corps Public Relations Office in 1945.