Command Structure of the US Army during WWII.
This is a generalization, but it illustrates the chain of command
Theater Command #1
Army Group #2
- Brigade #9
- Group #8
Battalion / Squadron #10
Company / Battery / Troop #11
#1. Theater Commands were normally names after the geographic region which the covered. Examples Mediterranean Theater of Operations or the North African Theater of Operations. In Major theaters of action there ware occasionally subordinate commands.
#2. Army Groups only came into play in the European Theater of
#7. Battalions when dealing with general orders only battalions not subordinate to a specific regiment come into play. You will know if a battalion is subordinate by its numerical designation. If it is the 1st, 2nd or 3rd Battalion then it is very likely a battalion of a specific regiment.
#8. The term "Group" was used during WWII by the Army Ground Forces as a way to control a number of independent battalions of the same branch of service operating under the same superior command.
#9 Brigade is an organization that is larger than a regiment but smaller than a division. Like a group it was used to control several subordinate units of the same branch of service. But brigades were usually large than groups.
#10 Squadrons are air force and cavalry units and are equivalent
#11 Troop is the company level equivalent for cavalry units, artillery units use the term battery all other units use the term company.
*Please note that some units don't follow this nice flow chart. With in a average infantry division for example there are 3 infantry regiments, 4 field artillery battalions, combat engineer battalion, medical battalion, signal company, quartermaster company, ordnance company, military police platoon, headquarters battery division artillery, division headquarters company, and a headquarters special troops.
** Armored division vary from infantry divisions in a number of ways. But this is complicated because there was heavy and light armored division organization structure.
*** not every unit was assigned to a division. If not then the unit reported through a group, brigade or directly to a corps, army, army group or theater level of command. These assignments changed very often making it difficult to state that any one unit was always assigned to a specific higher headquarters above division level. What makes locating decorations to members of these units difficult is the fact that they did serve normally in various superior commands and were occasionally attached to a specific division. Because of this you may find the person cited in the general orders of the division to which his unit was attached to or in the orders of the corps, army, army group or command to which they were assigned.