[1] On 18 July, the War Department designated National Guard troops of these three states to form the 31st Division.

However, the units that were to form the 31st did not begin concentration until 25 August, when Major General Francis Joseph Kernan took command.

[2] On 1 September, the 31st was reorganized in accordance with the tables of organization of 8 August, which called for a square division with four infantry regiments.

[3] The division began its overseas movement in September, relocating via Camp Mills to the Brooklyn, Hoboken, and New York Ports of Embarkation.

The troops in England spent a brief period in rest camps, then moved to Brest through Cherbourg and Le Havre.

Once in France, the 31st was planned to become the seventh depot division, a cadre formation responsible for processing replacements and forwarding them to frontline units.

Two days later, the division headquarters, both infantry brigades, the 116th Machine Gun Battalion, 106th Supply Train, and 106th Train Headquarters and Military Police moved to Le Mans, with some units relocating through the Loches area, while the remaining units were detached from the division when they arrived at Brest.

On 29 October, the division was ordered to be further reduced to a record cadre numbering 10 officers and 102 men, although the 56th Field Artillery Brigade was detached to Camp Coëtquidan for training.

The 106th Sanitary Train, which had remained at Brest, relocated to Camp de Souge on 25 November, and thence to the American Embarkation Center at Le Mans in December, where it was skeletonized.

On 27 November, the record cadre and 56th Field Artillery Brigade (without the 106th Trench Mortar Battery) moved to Brest, from which they sailed aboard the USS Manchuria between 9 and 10 December.

[8] Under the National Defense Act of 1920, the 39th Division was allotted to Alabama, Arkansas, Florida, Louisiana, and Mississippi, part of IV Corps, in 1921.

During the interwar period, the division did not train together in most years, as separate summer camps were held for the units of each state.

Between 17 and 23 December 1939, the division staff conducted supplementary winter training at Jackson Barracks to prepare for the upcoming Louisiana Maneuvers.

[9] As a result of World War II, the division was mobilized along with the entire National Guard and inducted into federal service on 25 November 1940 at home stations.

After being brought to war strength by the assignment of Selective Service draftees from its home area of Alabama, Florida, Louisiana, and Mississippi, the division participated in the IV Corps Louisiana Maneuvers in August 1941, the GHQ maneuvers near Good Hope Church between September and October as part of IV Corps, and the First Army Carolina Maneuvers near Ruby and Chesterfield, South Carolina during October and November as part of IV Corps, before returning to Camp Blanding.

During mid-1942, six National Guard divisions were used as "virtual pools" by the Army Service Forces to provide cadres and fillers for thousands of new service units not previously envisioned in the Army troop basis, many earmarked for the upcoming Allied invasion of Axis-occupied French North Africa.

The 31st Infantry Division arrived in Oro Bay, New Guinea, 24 April 1944, and engaged in amphibious training prior to entering combat.

The combat team moved up to advanced positions and took part in the general offensive launched 13 July, including the bloody Battle of Driniumor River.

Meanwhile, the remainder of the division relieved the 6th Infantry Division in the Sarmi-Wakde island area, 18 July 1944, built bridges, roads, and docks, patrolled the area, and engaged small units of the enemy, trying not to provoke a large scale counterattack by the enemy.

In mid-August the division began to stage for a landing on Morotai, leaving Aitape and Maffin Bay, 11 September 1944.

Moving up the Sayre Highway and driving down the Kibawe-Talomo trail, fighting in knee-deep mud and through torrential rains, the 31st forced the enemy to withdraw into the interior and blocked off other Japanese in the Davao area.

With the end of hostilities on 15 August, the 31st and the Philippine Commonwealth military were accomplished the surrender of all Japanese forces remaining in Mindanao.

[11] The 31st Infantry (NGUS) Division was effectively reformed with units from Alabama and Mississippi, with its headquarters moving to Mobile on 10 December 1956 and back to Birmingham on 2 May 1959.