Corps areas with corps mobilization responsibilities, 1921.
United States Army
<a rel="nofollow" class="external text" href="https://www.armyupress.army.mil/Portals/7/combat-studies-institute/csi-books/OrderofBattle1.pdf">US Army Order of Battle  1919–1941  Volume 1  The Arms: Major Commands and  Infantry Organizations, 1919–41 by  Steven E. Clay</a>