Military Ranks

Known pre-war US Armed Forces ranks
Known pre-war US Armed Forces ranks were:
 * Private, eg. Private Dobbs and Private Callow, stored at the Sierra Army Depot,
 * Corporal, eg. Corp. Dixon, serving at the Sierra Army Depot in 2077, Corp. Armstrong the Great Midwest Commonwealth 4th or 13th Armored Infantry Division soldier in 2077 (van Buren demo character) or Corp. Ben Shilling, serving at the Mariposa Military Base in 2077 (van Buren background character),
 * Sergeant, eg. Sgt. Platner, serving at the Mariposa Military Base in 2077 and Sgt. Dennis Allen (in year 2134, 57 years after the War, Brotherhood of Steel member in fact),
 * Captain, eg. Cap. Roger Maxson, serial number 072389, serving at the Mariposa Military Base in 2077 as security guard (MP) there, an active commanding officer there following the untimely death of Colonel Robert Spindel, or Cap. John Bloch, Blackfoot tribe founder (van Buren background character),
 * Major, eg. Maj. Barnett, in charge at the West Tech facility (CO of the security squad probably),
 * Colonel, eg. Col. Robert Spindel, CO of the security squad at the Mariposa Military Base, or Col. Green, the head of security and operations at the Los Alamos Nuclear Testing Facility (experience level 15 as a ghoul, van Buren character),
 * General, eg. Gen. Clifton, in charge at the Sierra Army Depot in 2077.

Ranks in the Enclave Armed Forces
Main article: Enclave of the United States Armed Forces organization

The Enclave of the United States of America was legal continuation of the pre-war USA. Its ranks were:
 * Private: also: Troop, Soldier, Guard; Guards at Camp Navarro were called soldiers by senior staff (also: Private First Class - described as pfc-tech, grade X, a soldier in a duty uniform, found at one of Navarro dialogue file Cctech.msg)
 * Sergeant, the only encountered by Chosen One NCO position, eg.:
 * Sgt. Bracks - in charge at the Enclave Patrolmen checkpoint 3 in Mariposa Military Base, K.I.A. there,
 * Sgt. Dornan - drill Sergeant at Camp Navarro, the only sergeant there (referred just as a "Sarge" by other personnel), had some insignia on the breastplate (like other military personnel there),
 * Sgt. Granite - leader of the Enclave Control Company squad, had Sergeant's chevrons on his shoulder,
 * some Sergeants on the oil rig: guards were floating "nothing to report Sarge", dr. Curling was going to complain to some Sergeant,
 * Captain - the only example known was Cap. Pickard, in charge at the Enclave Patrolmen checkpoint 1 in Mariposa Military Base, K.I.A. there; the highest rank known the Enclave Patrolman also (notice: in the contemporary US Army a Captain typically commands company-size unit, 62 to 190 soldiers),
 * Lieutenant Colonel - the only known example was Lt. Col. dr. Charles Curling, head of the United States Chemical Corps, reporting to the Cabinet (notice: in the contemporary US Army a Lieutenant Colonel typically commands a battalion-sized unit, 300 to 1000 soldiers),
 * Colonel - the only known example was Col. Sanders, CO for Mariposa Military Base excavation, the highest rank known officer, the highest rank known officer present on the field also, subordinated to the CHQ then (notice: in the contemporary US Army a Colonel typically commands brigade-sized units, 3000 to 5000 soldiers).
 * General (presence confirmed in pre-war armed forces and in NCR army only, however Col. Sanders had to be subjugated to somebody in CHQ).

Undefined ranks military staff:
 * There are 2 positions at Camp Navarro with undefined rank:
 * the Base Commander, the superior officer there, a long-serving soldier (referred as "old man" by his door guard, but described as "she" by the game engine); at least Base Commander should have the lowest officer's rank at the Enclave armed forces; under his command was 39 crew outpost, which was not only an ordinary platoon equivalent, but independent unit on the mainland also (notice: (1) in contemporary US Army the lowest officers grade is Second Lieutenant, that usually commanding platoon size units; (2) the lowest known officers grade in the Enclave armed forces was Captain; (3) Camp Navarro Base Commander responsibility was greater then ordinary platoon leader, (4) known pre-war persons in charge in research or military bases were officers of Major, Colonel or General rank),
 * the Quartermaster.
 * The United States Chemical Corps scientists had no military ranks. The only exeption was Chemical Corps head with Lt. Col. rank. However they were mentioned in Fallout Bible as officers.

2241 status
The only encountered by Chosen One part of the NCR army were New California Rangers. There is no knowledge about their ranks. It is not certain, if Shady Sands gate guard was part of NCR army, however its head was official with Captain position.

According to one of Fallout 2 endings shaken by the assassination of Vice-President Carlson, right-wing elements seize control of the NCR Congress and set the New California Republic on the path to military rule. Eventually the survivors of the Enclave find a home in the ranks of NCR.

2253 status
It is not certain, if the NCR got under military rule after destruction of the Enclave and if the survivors of the Enclave found a home in the ranks of NCR. At least one of them, Arcade Grannon, joined Followers of the Apocalypse however. It is known also, that the NCR army mimicked some pre-war armed forces ranks. During long war against Brotherhood of Steel following destruction of the Enclave in the NCR army were present such ranks as:
 * Corporal, eg. Corp. Christina Royce (position mentioned by Chris Avellone only, in fact as: "Corporal, the NCR lieutenant"),
 * Sergeant, eg. Sgt. Larsen, leader of the team escorting the NCR scientists to the Boulder (experience level 8),
 * Lieutenant, eg. Lt. Pierce (Pierce’s position mentioned only by Chris Avellone),
 * Captain, eg. Cap. Pierce (experience level 12), leader of the team escorting Gen. Coleridge, or Cap. Davidson (experience level 25),
 * Major, eg. Maj. Briggs, the 5th Engineering Company CO in 2247 (experience level 12) or Maj. Jack Fleming, the commander of the Hoover Dam NCR troops and governor Dodge's right hand man (experience level 15),
 * General, eg. Gen. Coleridge (experience level 20).

Vault City Guard
Vault dwellers claimed to be U.S. citizens (they were pre-war U.S. citizens' descendants and they were aware of this fact). Safehouse Project initially was developed by government, as well as Vault Behavioral Project. Vault City Guard was direct descendant of Vault security team - a Vault police force. Vault City Guard acted as universal military force, enforcing the law within town, defending it and securing Vault City perimeter. Vault City Guard positions were:
 * Guard,
 * Sergeant - the only Sargeant in 2241 in Vault City was Sargeant Citizen Stark, in charge with Corrections Center and acting commander of Vault City Guard,
 * Captain - commander of Vault City Guard, appointed by Vault City First Citizen, in 2241 vacat.

Consolidated ranks list

 * Private,
 * Corporal (presence confirmed at pre-war armed forces and mentioned by Chris Avellone),
 * Sergeant,
 * Lieutenant (mentioned by Chris Avellone only in connection with NCR army only),
 * Captain,
 * Major (presence confirmed at pre-war armed forces and in NCR army),
 * Lieutenant Colonel,
 * Colonel,
 * General (presence confirmed at pre-war armed forces and at the New California Republic army, however Col. Sanders had to be subjugated to somebody at the Enclave CHQ).