The headquarters was concurrently initiated at Detroit, Michigan, with Organized Reserve personnel previously assigned to the demobilized XVI Corps (RAI).

The XVI Army Corps was not activated prior to World War II and was located in Detroit as of 7 December 1941 in a reserve status.

During World War II, XVI Corps fought in the European Theater of Operations as part of the Ninth United States Army.

During this time, the Corps oversaw a number of Army Reserve units in the southwestern mid-West and the mountain states.

This turned out to be mostly fire suppression, because ..Robert McNamara had just announced the Reserves should be merged with the National Guard.