Parent regiment

Many armies use different regimental systems. The United States Army, among others, uses the parent regiment system.

In this system, adopted in 1957 under the Combat Arms Regimental System, or CARS, regiments are simply there to preserve units' lineage, and few regiments actually are complete organizations. The few remaining complete regiments, which actually retain the designation "regiment", are the Armored Cavalry Regiments, the 3d U.S. Infantry Regiment, and the 75th Ranger Regiment. Rather, the regiments are split into battalions (infantry, usually three) or squadrons (cavalry, usually three or more). Artillery can be split into battalions, batteries, or other units, depending on the type. These battalions are the actual combat units. For example, West Point is garrisoned by the 1st Battalion, 1st Infantry. However, the actual unit, the "1st Infantry", technically does not exist in military unit terms.

This system has been adopted only recently (about 1953) by the U.S. Army. Before then, it used the traditional regimental system, where regiments were actual combat units. This change can be viewed in the following examples:

Order of Battle: 1862 US Army

(This is just a fictional example)

:1st Cavalry Brigade/1st Cavalry Division/Cavalry Corps/Army of the Potomac::1st United States Cavalry Regiment::3rd United States Cavalry Regiment::24th New York Volunteer Cavalry Regiment::25th New York Volunteer Cavalry Regiment::Battery B, 1st New York Light Artillery Regiment

Order of Battle: 2000 US Army

(This is just a fictional example)

:1st Brigade/1st Cavalry Division/U.S. Third Army::1st Battalion, 5th Cavalry Regiment::2d Squadron, 7th Cavalry Regiment::1st Battalion, 8th Cavalry Regiment::5th Battalion, 82nd Field Artillery Regiment::82d Engineer Battalion::24th Brigade Support Battalion

Parent Units in other Forces

In Commonwealth Militaries the Parent Unit is used to denote the first unit an officer or an enlited man was posted to after training.