3d Division Order of Battle, 1918

The order of Battle for the 3d Division, which we've been discussing here recently.

All US divisions in World War One were big "square" divisions, much larger than those which the US went to after 1940. Indeed, they were absolutely enormous compared to the divisions of other armies, in part because the U.S. was capable of fully manning a division. Generally, U.S divisions contained at least 30,000 men, but some would swell up beyond that. The 3d Division is an example of that. By October 1918 it contained 54,000 men, well three times the size of a World War Two Division.

Indeed, this impacts histories of the war as many histories fail to note how large US divisions were.  As we'll see, in the Battle of Belleau Wood the 2nd Division took on elements of five German divisions. But by 1918 German divisions were rarely fully manned. For that matter, Allied ones were rarely fully manned either.  So while histories may note that one army or another had "x" divisions here and there, while the US had only "y", the US commitment at any one time was often much larger than those numbers would suggest.

Anyhow, the 3d Division was made up mostly of Regular Army units. For that reason, it was one of the first divisions in France and one of the first combat ready divisions.  As the U.S. Army did not keep divisions formed during peacetime, it was assembled just prior to the war.  Nonetheless, it was largely made up of Regular Army soldiers augmented in some areas, to flesh it out, with National Guardsmen (most likely) or recent inductees from civilian life.

Here's how the unit was formed.

Headquarters, 3rd Division

5th Infantry Brigade, consisting of;

4th Infantry Regiment, a regular Army regiment.

7th Infantry Regiment, also a regular regiment

8th Machine Gun Battalion.  I don't know the make up of this unit but machine gun battalions were a recent introduction into the Army.  World War One would prove to be unique for the combat use of such battalions and they'd not really reappear in the U.S. Army during World War Two.

6th Infantry Brigade, consisting of;

30th Infantry Regiment. Regular Army.

38th Infantry Regiment.  Regular Army.

9th Machine Gun Battalion

3rd Field Artillery Brigade, consisting of;

10th Field Artillery Regiment (75 mm)  Newly formed in 1916 at Camp Douglas, Arizona.

18th Field Artillery Regiment (155 mm).  Newly formed in 1916 at Ft. Bliss, Texas.

76th Field Artillery Regiment (75 mm).  Converted from regular U.S. Army's 18th Cavalry Regiment wholesale.  The 18th Cavalry was a newly formed Cavalry regiment authorized in 1916 which had a brief existence before being converted to cavalry Quite a few of the newly authorized cavalry regiments from the National Defense Act of 1916, and National Guard cavalry regiments, were reorganized from cavalry to artillery or transport.  Indeed, even some National Guard infantry was so reorganized.  The reorganization of available cavalry regiments made sense in context as the men in them were familiar with handling horses, and artillery was horse drawn at the time.

3rd Trench Mortar Battery.  Another new formation. Trench mortars were a major feature of World War One but would be obsolete by World War Two.

7th Machine Gun Battalion

6th Engineer Regiment

5th Field Signal Battalion

Headquarters Troop, 3rd Division.  This was a cavalry troop.  I'm not sure what cavalry regiment provided the troops for it.  Basically, however, cavalry troops were individual troops assigned from prewar cavalry regiments, quite a few of which were National Guard cavalry troops.

3rd Train Headquarters and Military Police.  Military police as a regular establishment was new to the Army at this time, and reflected its enormous growth.

3rd Ammunition Train.

3rd Supply Train

3rd Engineer Train

3rd Sanitary Train

5th, 7th, 26th, and 27th Ambulance Companies and Field Hospital