This is the structure of a typical WWII U.S. Army Infantry Division.

A Infantry Division had appr. 14000 men and was commanded by a Major General.

Each Infantry Regiment (appr. 3250 men, commanded by a Colonel) consist of the following units:
- 1st Battalion (appr. 870 men, commanded by a Luitenant-Colonel)
- 2nd Battalion (appr. 870 men, commanded by a Luitenant-Colonel)
- 3rd Battalion (appr. 870 men, commanded by a Luitenant-Colonel)
- HQ Company (appr. 110 men, commanded by a Captain)
- AT Company (appr. 165 men, commanded by a Captain)
- Cannon Company (appr. 120 men, commanded by a Captain)
- Service Company (appr. 115 men, commanded by a Captain)
- Medical Detachment (appr. 135 men, commanded by a Major)

Each Battalion consist of the following units:
- Rifle Company * (appr. 190 men, commanded by a Captain)
- Rifle Company * (appr. 190 men, commanded by a Captain)
- Rifle Company * (appr. 190 men, commanded by a Captain)
- HQ Company (appr. 125 men, commanded by a Captain)
- Heavy Weapon Company * (appr. 165 men, commanded by a Captain)

* The Companies where A, B, C and D (Heavy Weapons) for the 1st Battalion of a Regiment, E, F, G and H (Heavy Weapons) for the 2nd Battalion of a Regiment and I, K, L and M (Heavy Weapon) for the 3rd Battalion of a Regiment.

Each Rifle Company consist of three Rifle Platoons, a Weapons Platoon and a HQ Section.
Each Heavy Weapon Company consist of two Heavy Machine Gun Platoons, a Heavy Mortar Platoon and a HQ Section.
Each of these Platoons was commanded by a Second Luitenant or a First Luitenant.

More information about the structure of an Infantry Division on a detailed scale can you find on the site of the 100th Infantry Division Association.