On 7 October 1920, the 1st Division organized under the peacetime TO&E, which included two organic infantry brigades of two infantry regiments each, one engineer regiment; one observation squadron; one field artillery brigade of two field artillery regiments; one medical regiment; one division quartermaster train; and a special troops command replacing the remainder of the division train. The total authorized strength of this TO&E was 19,385. 1st Division was one of three infantry divisions and one cavalry division that was authorized to remain at full peacetime strength. It was the only Regular Army division assigned to the Second Corps Area, which also included the 27th Infantry Division of the New York National Guard; the 44th Infantry Division of the New Jersey, New York, and Delaware National Guards; the 21st Cavalry Division of the New York, Pennsylvania, Rhode Island, and New Jersey National Guards; and the 77th, 78th, and 98th Infantry Divisions and the 61st Cavalry Division of the Organized Reserves. This was the organization that existed in the Second Corps Area for the duration of the Interbellum period.