The National Guard was a reserve component of the United States Army and served as a domestic defense and disaster relief force during peacetime. However, during wartime, they were also deployed abroad as front-line troops alongside other Army units. The US National Guard was made up out of the National Guards of the various Commonwealths.
Many National Guard units were dispatched to prepare for the likely event that China would attack American soil with nuclear weapons. Units from both the National Guard of the Commonwealth of Columbia and the National Guard of the Eastern Commonwealth were widely active in the Columbia Commonwealth and the Greater Washington area in the time prior to, during and following the Great War. In particular areas, like Washington D.C., National Guard units were mobilized to provide security and assist in the evacuation of civilians from the city and its outlying areas in coordination with National Catastrophe Relief Auxiliary units. Other units dealt with riot control, particularly during the Automation riots. Following a walkout at Poseidon Energy Plant WV-06, Brent Olson called in the National Guard, who broke up the protest using violent means and gas grenades developed by HalluciGen.
The Capital Wasteland still has a widespread traces of the National Guard. National Guard checkpoints can be found dotted around the Capital Wasteland. These checkpoints are usually guarded by Army robots and contain radiation warning signs alerting people that they are near a highly irradiated area. A National Guard detachment from Pennsylvania was deployed to Germantown in the immediate aftermath of the Great War as mentioned in the terminal entries of Nancy Kroydon, Presiding officer of the National Catastrophe Relief Auxiliary - Response Unit MD-478, which was also deployed to Germantown on evacuation detail. With the nuclear holocaust on October 23, 2077, and the dissolution of the chain of command, the National Guard and the rest of the United States Armed Forces effectively ceased to exist, becoming groups of isolated soldiers with no coordination and many deserted or succumbed to the blasts and nuclear fallout of the war.
- National Guard depot - Headquarters of the Columbia Commonwealth National Guard.
- National Guard training yard - Training yard and armory for the 1st battalion, 101st Field Artillery Regiment, located north of Boston.
- Spanish Fork Armory - an National Guard armory within the town is the source of high powered weapons for the White Legs tribe, particularly their signature weapon the "Storm drum".
Main article: Fallout 3 military checkpoints
Main article: Fallout 4 military checkpoints
- Army fatigues
- Combat armor including Riot gear
- Military fatigues
- Power armor, mostly older T-45 variants (though a few elite units and high level commands within the NG had access to extremely limited numbers of T-51 models)
- Recon armor
- Tesla armor
- A range of hand grenades including fragmentation, pulse, and plasma grenades
- Various types of land mines
- Mini nukes
- Plastic explosives including Cordex
- Combat knives
- Combat shotguns
- Experimental MIRV (At least one example was delivered to the National Guard Depot in D.C. shortly before the Great War, presumably for test & evaluation purposes.)
- Gatling lasers
- Gauss rifles, including the M72
- Different types of grenade launchers including the grenade machinegun
- Wattz 2000 & AER9 laser rifles
- Wattz 1000 & AEP7 laser pistols
- Light support weapon
- M199 5.56mm assault rifle (Mentioned only, not seen to date in series)
- N99 10mm pistol
- R91 5.56mm assault rifle
- Military Ripper
- Sniper rifles, including the DKS-501 (.308 variant)
- Submachine guns, including the .45 Auto submachine gun and M3A1 "grease gun" SMG
- Various types of Missile & rocket launchers
- Winchester P94 plasma rifle (Also known as a plasma caster)
- Cyberdogs, including the Cyberhound Mk III military model
- Mister Gutsies
- Sentry bots
- Nate served in the 2nd Battalion, 108th Infantry Regiment, which is a real regiment in the New York Army National Guard.
- At the outbreak of the Sino-American War, totally separate from the NG at both commonwealth and national level, the various Commonwealths began raising armored infantry divisions on a basis similar to that of the state volunteer regiments which served in the American Civil War and other 19th and early 20th Century conflicts. While part of the regular Army operationally, administratively these Commonwealth divisions enjoyed considerable autonomy where oversight by the Department of the Army in particular, and the federal government in general, was concerned. As their name suggests, the armored infantry divisions primarily consisted of power armor equipped units; at least initially their power armor suits were early versions of the T-45 power armor. Known formations mustered under this system included the Great Midwest Commonwealth 13th Armored Infantry Division and the 4th Armored Infantry Division, Great Midwest Commonwealth.