ORDER of BATTLE
Submitted by Richard A. Rinaldi © 1999
ARVN
South Vietnam had a Joint General Staff, in command of all of the armed
forces. In the Army, most forces came under the commander of a corps. These were
geographic units, known as corps tactical zones (CTZ) and later as military
regions (MR).
The original Army organization grew from seven divisions to four corps
tactical zones (IIV) and nine divisions. From north to south:
I Corps
 1^{st} Infantry Division (1^{st}, 2^{nd}
and 3^{rd} Infantry Regiments?)
 2^{nd} Infantry Division (4^{th}, 5^{th} and 6^{th}
Infantry Regiments?)
 51^{st} Infantry Regiment.
II Corps
 22^{nd} Infantry Division (40^{th}, 41^{st}
and 47^{th} Infantry Regiments?)
 23^{rd} Infantry Division (44^{th} and 45^{th}
Infantry Regiments?)
 42^{nd} Infantry Regiment.
III Corps
 5^{th} Infantry Division (7^{th}, 8^{th}
and 9^{th} Infantry Regiments?)
 25^{th} Infantry Division (46^{th}, 49^{th} and
50^{th} Infantry Regiments?)
 43^{rd} and 48^{th} Infantry Regiments.
IV Corps
 7^{th} Infantry Division (10^{th}, 11^{th}
and 12^{th} Infantry Regiments?)
 9^{th} Infantry Division (14^{th}, 15^{th} and
16^{th} Infantry Regiments?)
 21^{st} Infantry Division (31^{st}, 32^{nd}, and
33^{rd} Infantry Regiments?).
There were also armor, ranger, airborne, and marines units (see sections
below on them). GHQ artillery included six battalions of 155mm howitzers, and
some separate batteries of 75mm guns and 105mm howitzers equivalent to another
four battalions.
 1^{st} Infantry Division was headquartered near Hue for its
existence.
 2^{nd} Infantry Division was originally at Da Nang, moving
its headquarters to Quang Ngai in May 1965, then to Chu Lai in early 1972.
 5^{th} Infantry Division was headquartered at Phu Loi from
Jul 1964, moving to Lai Khe Feb 1970.
 7^{th} Infantry Division had its headquarters at My Tho,
moving to Dong Tam (near My Tho) in Sep 1969; Dong Tam had been the base
camp for the 9^{th} [U.S.] Infantry Division.
 9^{th} Infantry Division had its headquarters at Sa Dec
until Apr 1972, when it moved to Vinh Long (a former U.S. base).
 21^{st} Infantry Division was headquartered at Bac Lieu.
 22^{nd} Infantry Division had its headquarters at Kontum
until Mar 1965, when it moved to Ba Gi.
 23^{rd} Infantry Division had its headquarters at Ban Me
Thuot.
 25^{th} Infantry Division had its headquarters at Duc Hoa
from Dec 1964. It moved to Cu Chi (former base camp of the U.S. 25^{th}
Infantry Division) Dec 1970.
Around 1959, a division totaled 10,450 personnel (three infantry regiments,
105mm howitzer battalion, 4.2" mortar battalion, reconnaissance company,
and pioneer battalion). This was unchanged at the end of 1964, although the 23^{rd}
Division had only two infantry regiments assigned. From summer 1965, all
infantry regiments began forming fourth battalions.
The 10^{th} Infantry Division was activated 16 May 1965 at Xuan Loc,
in III CTZ (taking in the exiting 43^{rd} and 48^{th} Infantry
Regiments and the new 52^{nd} Infantry Regiment); it was renumbered by
the end of the year (or as late as Jan 1967?) as 18^{th} Division. A new
separate infantry regiment was authorized Nov 1965. In addition, all infantry
divisions began replacing the mortar battalion with a second battalion of 105mm
howitzers. The 23^{rd} Infantry Division acquired a third regiment (53^{rd}
Infantry Regiment) in 1967 or 1968. In early 1968 all divisions were authorized
three 105mm and one 155mm artillery battalions.
Overall organization mid 1968 included the 10 divisions, 3 separate
regiments, airborne division, Ranger command (20 bns), and 11 armored cavalry
bns. Artillery expanded after that point; by the end of 1970 there were 43
battalions of 105mm howitzers and 15 battalions of 155mm howitzers; divisions
actually had 46 of the battalions, exceeding the number arrived at by assuming
three 105mm and one 155mm battalion each (40 battalions). Spring 1970 saw the
authorization of two 175mm gun battalions and two AA battalions (40mm AA and
quad .50). Increases in armor were also authorized.
In 1971, infantry regiments were reduced to three battalions again, but each
battalion was reorganized with four companies. The 3^{rd} Infantry
Division was activated 1 Oct 1971 in I CTZ. Its headquarters was established at
Ai Tu, near Quang Tri city. After the loss of Quang Tri in 1972, it was
reconstituted at Da Nang. By this date, all of the separate regiments were
incorporated into divisions. Following the 1972 Easter offensive, two more AA
battalions and three more 175mm gun battalions were authorized.
December 1972 organization
 1^{st} Inf Div (MR I: Hue)  1^{st}, 3^{rd}, 51^{st},
54^{th} Inf Regts
 2^{nd} Inf Div (MR I: Quang Ngai)  4^{th}, 5^{th},
6^{th} Inf Regts
 3^{rd} Inf Div (MR I: Quang Tri)  2^{nd}, 56^{th},
57^{th} Inf Regts
 22^{nd} Inf Div (MR II: Bai Gi)  40^{th}, 42^{nd},
47^{th} Inf Regts
 23^{rd} Inf Div (MR II: Ban Me Thuot)  41^{st}, 44^{th},
45^{th}, 53^{rd} Inf Regts
 5^{th} Inf Div (MR III: Lai Khe)  7^{th}, 8^{th},
9^{th} Inf Regts
 18^{th} Inf Div (MR III: Xuan Loc)  43^{rd}, 48^{th},
52^{nd} Inf Regts
 25^{th} Inf Div (MR III: Duc Hoa)  46^{th}, 49^{th},
50^{th} Inf Regts
 7^{th} Inf Div (MR IV: Dong Tam)  10^{th}, 11^{th},
12^{th} Inf Regts
 9^{th} Inf Div (MR IV: Rach Gia)  14^{th}, 15^{th},
16^{th} Inf Regts
 21^{st} Inf Div (MR IV: Bac Lieu)  31^{st}, 32^{nd},
33^{rd} Inf Regts
 Abn Div (GR: Saigon)  1^{st}, 2^{nd}, 3^{rd} Abn
Bdes, 7^{th} Ranger Gp
 Marine Div (GR: Saigon)  147^{th}, 258^{th}, 369^{th}
Marine Bdes
 3^{rd} Rgr Cmnd (Bien Hoa)  3^{rd}, 5^{th}, 6^{th}
Ranger Groups
 MR 1 (Da Nang)  1^{st} Ranger Gp, HQ 1^{st} Armor Bde
 MR II (Pleiku)  2^{nd} Ranger Gp, HQ 2^{nd} Armor Bde
 MR III (Bien Hoa) 81^{st} Ranger Bn, HQ 3^{rd} Armor Bde
 MR IV Can Tho
 44^{th} Spec Tac Zone (at Chi Long)  4^{th} Ranger Gp,
HQ 4^{th} Armor Bde
 Armd Cav Regts: 18 (11 divisional, 7 separate)
 Ranger Bns: 22, plus 33 border ranger defense (successor to old Special
Forces CIDG), and 81^{st} Ranger "Force"
 105mm How Bns: 33 divisional, 8 separate, 3 airborne
 155mm How Bns: 11 divisional, 4 separate
 175mm Gun Bns: 5
 Air Defense Bns: 4 (40mm and quad .50 MG)
