Editing Army of the Republic of Vietnam (section)

==Formations and units==
The 1956 army structure of four conventional infantry divisions (8,100 each) and six light divisions (5,800 each) were reorganised according to American advice as seven full infantry divisions (10,450 each) and three corps headquarters by September 1959. The three armed services together numbered around 137,000 in 1960. In face of the communist threat, the army was expanded to 192,000 with four corps, nine divisions, one airborne brigade, one SF group, three separate regiments, one territorial regiment, 86 ranger companies, and 19 separate battalions, as well as support units in 1963, and a force strength of 355,135 in 1970.<ref name=Collins31>{{cite book|first=James L.|last=Collins|title= The Development and Training of the South Vietnamese Army, 1950–72|publisher=[[Department of the Army]]|url=https://history.army.mil/html/books/090/90-10/cmhPub_90-10.pdf|place=Washington DC|date=1975 |orig-date=Preface dated 15 April 74|pages=31, 86|archive-url=https://web.archive.org/web/20230418070331/https://history.army.mil/html/books/090/90-10/cmhPub_90-10.pdf|archive-date= April 18, 2023}}</ref> Meanwhile, the supporting militia forces grew from a combined initial size of 116,000 in 1956, declined to 86,000 in 1959, and then were pushed up to 218,687 RF & 179,015 PF in 1970.<ref name=Collins31 /> The effect of expanding the total land force from about 220,000 in 1960 to around 750,000 in 1970 can be imagined, along with the troop quality issues that resulted.

===High Command===
{{main|Joint General Staff}}

===Corps===
* [[I Corps (South Vietnam)|I Corps]]/CTZ
* [[II Corps (South Vietnam)|II Corps]]/CTZ
* [[III Corps (South Vietnam)|III Corps]]/CTZ
* [[IV Corps (South Vietnam)|IV Corps]]/CTZ
* 44th Special Tactical Zone

===Divisions===
* [[1st Division (South Vietnam)|1st Infantry Division]] – The French formed the 21st Mobile Group in 1953, renamed 21st Division in January 1955, the 1st Division later that year. Both the 1st and 2nd Divisions were established, Gordon Rottman writes, on January 1, 1959.<ref>Gordon L. Rottman, "Army of the Republic of Vietnam 1955–75," Osprey, 2012.</ref> Considered "one of the best South Vietnamese combat units". Based in Huế, it had four rather than three regiments. Component units:
** 1st, 3rd, 51st and 54th Infantry Regiments
** 10th, 11th, 12th and 13th Artillery Battalions
** 7th Armoured Cavalry Squadron
** US Advisory Teams 3 and 4 (renumbered 18 and 19 in 1968)
* [[2nd Division (South Vietnam)|2nd Infantry Division]] – The French formed the 32nd Mobile Group in 1953, renamed 32nd Division in January 1955, then the 2nd Division later that year. Based in Quảng Ngãi, it was considered a "fairly good" division. Component units:
** 4th, 5th and 6th Infantry Regiments
** 20th, 21st, 22nd and 23rd Artillery Battalions
** 4th Armoured Cavalry Squadron
** US Advisory Team 2 (renumbered 17 in 1968).
* [[3rd Division (South Vietnam)|3rd Infantry Division]] – Raised in October 1971 in Quảng Trị. One regiment was from the 1st Division (the 2nd Inf Regt). Based at Da Nang. It collapsed in the 1972 [[Easter Offensive]], was reconstituted, and was destroyed at Da Nang in 1975. Component units:
** 2nd, 56th and 57th Infantry Regiments
** 30th, 31st, 32nd and 33rd Artillery Battalions
** 20th Armoured Cavalry Squadron
** US Advisory Team 155
* [[5th Division (South Vietnam)|5th Infantry Division]] – Originally formed in North Vietnam as the 6th Division (commonly known as the "Nung" division), and renamed the 3rd Field Division after its move to Song Mao then to the 5th Division in 1959. Many [[Nùng people|Nungs]] originally were in its ranks. It was at Biên Hòa in 1963 and was involved in the overthrow of Diệm. It then operated north of Saigon. It entered Cambodia in 1970 and defended An Lộc in 1972. Component units:
** 7th, 8th and 9th Infantry Regiments
** 50th, 51st, 52nd and 53rd Artillery Battalions
** 1st Armoured Cavalry Squadron
** US Advisory Team 70
* [[7th Division (South Vietnam)|7th Infantry Division]] – Formed as the 7th Mobile Group by the French, it became the 7th Division in 1959. Served in Mekong Delta 1961–75. Component units:
** 10th, 11th and 12th Infantry Regiments
** 70th, 71st, 72nd and 73rd Artillery Battalions
** 6th Armoured Cavalry Squadron
** US Advisory Team 75
* [[9th Division (South Vietnam)|9th Infantry Division]] – Formed in 1962, northern Mekong Delta. Component units:
** 14th, 15th and 16th Infantry Regiments
** 90th, 91st, 92nd and 93rd Artillery Battalions
** 2nd Armoured Cavalry Squadron
** US Advisory Team 60
* [[18th Division (South Vietnam)|18th Infantry Division]] – Formed as the 10th Division in 1965. Renamed the 18th Division in 1967 (number ten meant the worst in [[Military slang|GI slang]]). Based at Xuân Lộc. Made famous for its defence of that town for a month in March–April 1975. Component units:
** 43rd, 48th and 52nd Infantry Regiments
** 180th, 181st, 182nd and 183rd Artillery Battalions
** 5th Armoured Cavalry Squadron
** US Advisory Team 87
* [[21st Division (South Vietnam)|21st Infantry Division]] – The ARVN 1st and 3rd Light Divisions were formed in 1955, then renamed the 11th and 13th Light Divisions in 1956. They were combined to form the 21st Division in 1959. Served mainly near Saigon and in the Mekong Delta. Component units:
** 31st, 32nd and 33rd Infantry Regiments
** 210th, 211st, 212nd and 213rd Artillery Battalions
** 9th Armoured Cavalry Squadron
** US Advisory Team 51
* [[22nd Division (South Vietnam)|22nd Infantry Division]] – Initially raised as the 4th Infantry Division, which existed briefly in the 1950s, but was renamed the 22nd Division as four is considered an unlucky number in Vietnam (sounds in Vietnamese like the word for death). The ARVN 2nd and 4th Light Divisions were formed in 1955; the 4th was renamed the 14th Light Division in 1956. They were combined to form the 22nd Division in 1959. It served near Kon Tum and elsewhere in the Central Highlands. It collapsed in 1972, and in 1975 was in Bình Định province. It was evacuated south of Saigon as Central Highlands front fell, and was one of the last ARVN units to surrender. Component units:
** 40th, 41st, 42nd and 47th Infantry Regiments
** 220th, 221st, 222nd and 223rd Artillery Battalions
** 19th Armoured Cavalry Squadron
** US Advisory Team 22
* [[23rd Division (South Vietnam)|23rd Infantry Division]] – Originally the 5th Light Division, it was renamed 23rd in 1959. It operated in central Vietnam, and entered Cambodia in 1970. It fought well in 1972, successfully defending Kon Tum, but was shattered in 1975 while defending Ban Me Thout. Component units:
** 43rd, 44th, 45th and 53rd Infantry Regiments
** 230th, 231st, 232nd and 233rd Artillery Battalions
** 8th Armoured Cavalry Squadron
** US Advisory Team 33
* [[25th Division (South Vietnam)|25th Infantry Division]] – Formed in Quảng Ngãi in 1962, it moved to south west of Saigon in 1964. It entered Parrot's Break, Cambodia in 1970, and defended the western approaches of Saigon in 1972 and 1975. Component units:
** 46th, 49th and 50th Infantry Regiments
** 250th, 251st, 252nd and 253rd Artillery Battalions
** 10th Armoured Cavalry Squadron
** US Advisory Team 99
*[[Vietnamese Airborne Division|Airborne Division]] – originally formed by the French as the Airborne Group in 1955. Brigade strength by 1959, it was formed as division in 1965. Based at [[Tan Son Nhut Air Base]], it was used as a fire brigade throughout South Vietnam. It included 9 Airborne Battalions and 3 Airborne Ranger Battalions. It fought in Cambodia in 1970 and Laos in 1971. It was used as brigade Groups in 1975, the 1st at Xuân Lộc, the 2nd at Phan Rang, and the 3rd at Nha Trang. A 4th Brigade was added in 1974. Component units:
** 1st Airborne Brigade
*** 1st, 8th and 9th Airborne Battalions
*** 1st Airborne Artillery Battalion
** 2nd Airborne Brigade
*** 5th, 7th and 11th Airborne Battalions
*** 2nd Airborne Artillery Battalion
** 3rd Airborne Brigade
*** 2nd, 3rd and 6th Airborne Battalions
*** 3rd Airborne Artillery Battalion
** 4th Airborne Brigade
*** 4th and 10th Airborne Battalions
** US Airborne Advisory Team 162

=== Rangers, Special Forces, and Presidential Guard ===
[[File:ARVN Rangers defend Saigon, Tet Offensive.jpg|thumb|ARVN Rangers fighting in Saigon during the [[Tet Offensive]], 1968.]]
* [[ARVN Rangers]]<ref>The Organization of the Ranger Groups is highly tentative, as the battalions were rather frequently switched between different groups. As an example, the much decorated 34th Battalion served in different periods with the 3rd, 5th and 6th Groups.</ref> (Biệt Động Quân)
** 1st Ranger Group:<ref>Formed 1966. Attached to I Corps.</ref> 21st, 37th and 39th Ranger Battalions
** 2nd Ranger Group:<ref>Formed 1966. Attached to II Corps.</ref> 11th, 22nd and 23rd Ranger Battalions
** 3rd Ranger Group:<ref>Formed 1966. Attached to III Corps.</ref> 31st, 36th and 52nd Ranger Battalions
** 4th Ranger Group:<ref>Formed 1968.Attached to IV Corps.</ref> 42nd, 43rd and 44th Ranger Battalions
** 5th Ranger Group:<ref name="ReferenceA">Formed 1970. Attached to III Corps.</ref> 33rd, 34th and 38th Ranger Battalions
** 6th Ranger Group:<ref name="ReferenceA"/> 35th, 51st and 54th Ranger Battalions
** 7th Ranger Group:<ref>Formed 1973. Attached to the Airborne Division.</ref> 32nd and 85th Ranger Battalions
** 8th Ranger Group:<ref>Formed in 1974. (Possibly never fully operational)</ref> 84th and 87th Ranger Battalions
** 9th Ranger Group:<ref>Formed in 1975. (Possibly never fully operational)</ref> 91st and 92nd Ranger Battalions
** 81st Ranger Group:<ref>Actually just one single overstrength battalion. While included in the Ranger Command, it had strong links with the LLDB special forces, and used the LLDB green berrets.</ref> 81st Ranger Battalion (Airborne)
* [[ARVN Special Forces]] (Lực Lượng Đặc Biệt or LLDB)
* [[Presidential Guard (South Vietnam)|Presidential Guard]] (Lữ đoàn Liên binh phòng vệ Tổng Thống Phủ)

=== Armored units ===
* [[3d Armored Cavalry Squadron (South Vietnam)|3d Armored Cavalry Squadron]], II Corps
* [[20th Tank Regiment (South Vietnam)|20th Tank Regiment]], I Corps
* [[1st Armored Brigade (Vietnam)|1st Armored Brigade]] 
** 1st Armored Cavalry Regiment
** 2nd Armored Cavalry Regiment
** 3rd Armored Cavalry Regiment
** 4th Armored Cavalry Regiment                                                                                                                                                                
* [[2nd Armored Brigade (Vietnam)|2nd Armored Brigade]]  
** 5th Armored Cavalry Regiment
** 6th Armored Cavalry Regiment
** 8th Armored Cavalry Regiment
** 9th Armored Cavalry Regiment                                                                                                                                              
* [[3rd Armored Brigade]]
** 10th Armored cavalry Regiment
** 12th Armored Cavalry Regiment
** 13th Armored Cavalry Regiment
** 14th Armored Cavalry Regiment                                                                                                                                                                 
* [[4th Armored Brigade (Vietnam)|4th Armored Brigade]]
** 15th Armored Cavalry Regiment
** 16th Armored Cavalry Regiment
** 17th Armored Cavalry Regiment
** 18th Armored Cavalry Regiment
* 7th Armored Cavalry Regiment (independent unit)
* 11th Armored Cavalry Regiment (independent unit)                                                                                                                                             
* [[315th Armored Brigade]]                                                                                                                                               
* [[318th Armored Brigade]]                                                                                                                                            
* [[322nd Armored Brigade]]                                                                                                                                           
<gallery caption="Unit Flags">
File:Flag of ARVN Armored Cavalry Regiment.png|The flag of Army of the Republic of Vietnam's Armored Cavalry Regiment, used between 1957 and 1975.
File:Flag of Security Force of Capital Special Zone.svg|The flag of Security Force of Capital Special Zone, used between 1965 and 1975.
File:Flag of ARVN's Military Police.svg|The flag of the South Vietnamese Military Police Corps, used between 1955 and 1975.
File:Flag of ARVN's Artillery Forces.svg|The flag of the ARVN's Artillery Forces, used between 1951 and 1975.
File:Flag of ARVN Military Engineering Forces.svg|The flag of ARVN Military Engineering Forces, used between 1955 and 1975.
</gallery>