National Guard Depot

Located along the northern edge of Downtown DC, the National Guard Depot is a high-security compound that used to be the headquarters for the Washington militia. It can be reached from the wasteland, avoiding the metro system.

National Guard Armory
The Armory is only accessible after traversing the National Guard Depot, the National Guard Training Wing, the National Guard Depot Offices, then exiting from the Offices back to the National Guard Depot. Just as you zone back into the Depot, there is an electrical switch on the left straight ahead. When you throw the switch, you will see the rotating lights of the Armory's utility door turn on, two stories below where you just threw the switch. (You can't pick the utility door, even though it says it's a Very Hard door.) To get into the Armory itself, you will have to activate a second switch right inside the utility room - once activated, the floor will open and you will be able to enter the armory itself.

There is also a "glitch" way to get into the armory area, not into the armory vault itself as you need the Keller Family Transcripts. It is possible to jump to the electrical switch after entering the Depot by placing carts and trolleys near the door sticking out of the rubble, in the room with the Nuka-Cola machines and Eat-O-Matic's. This method can also be used to obtain access to the top floor of the building, also you can pick up a barrel and place it on the ramp next to the two turrets on the second floor.

In the armory, you will find the Bobblehead: Small Guns (which will increase your Small Guns skill permanently by 10) on a shelf next to the terminal for the bunker access. Additionally, you will find a Minigun, a Missile Launcher, four Assault Rifles, two 10mm SMGs, two 10mm Pistols and lots of ammo and supplies. Unfortunately, all of the weapons are in poor condition.

National Guard Bunker
The bunker, accessed through the armory, is opened by completing the unmarked quest Keller Family Refuge. Inside the bunker is the Experimental MIRV Fatman (and a plasma grenade hidden in a cooking pot on the first set of shelves left-hand side.) Also 5 Mini-Nukes next to MIRV and a Nuka-Cola Quantum in bin near back.

Nothing inside the bunker or armory seems to "reset" with time, so you can effectively use the entire bunker and armory as your home. There is a usable workbench (with a safe), fridge, beds, and plenty of storage boxes, tables and shelves. It's an ok free alternative, but compared to My Megaton House or Tenpenny Suite you do not have the option of getting any house improvements.

Depot

 * Nikola Tesla And You located in the National Guard Depot, in a storeroom on the lowest level (If you stand in front of the "Very Hard" door leading the armory), is the storeroom directly to your right in one of the shelfs.
 * Pre-War Book: two located in the National Guard Depot on the third floor, right in front of you if you go up the stair you see in your left after you enter from The Capital Wasteland.

Training Wing

 * Tales of a Junktown Jerky Vendor sitting on a desk located in Depot Training Wing after climbing a set of stairs and going through two doors. You walk through a collapsed section of wall from this room to the room with the Average Locked safe.
 * Pre-War Book in the room after the Tales of a Junktown Jerky Vendor (above the safe).
 * Random weapon along with ammo. Found in one of the 2 wooden gun cabinets in the same room as the 2 books above (Pre-War and Junktown Jerky Vendor).

Offices

 * Duck and Cover! located on a long counter in an irradiated section of the National Guard Offices portion.
 * One Pre-War Book one floor directly above that, next to a terminal in the third cubicle on the left.
 * Three more Pre-War Books in the National Guard Offices on the shelves in the center of an open collapsed two floor room.
 * Three Pulse Grenades.
 * Stealth Boy in an average wall safe, on the first floor of the Training Wing.

Armory

 * Five Mini Nukes and the unique Fatman "The Experimental MIRV".
 * The Bobblehead: Small Guns located on a shelf in the sealed storage room in the basement of the Armory.
 * A Nuka-Cola Quantum underneath the table, inside of the small bin, next to the refrigerator within the Keller shelter.
 * Four Assault Rifles and 5.56mm Round ammunition.
 * Missile Launcher and several Missiles.
 * A Minigun and 5mm Round ammunition.
 * Two 10mm SMGs, two 10mm Pistols and 10mm Ammo.
 * Lots of Rad-X, RadAway, Stimpacks, and some Buffout too.
 * Several bottles of Purified Water.
 * A copy of U.S. Army: 30 Handy Flamethrower Recipes on the bottom shelf, past the table to the left of the M.I.R.V.
 * All of the ingredients for a Nuka Grenade are located within the bunker (Nuka-Cola Quantum, Tin Can, Abraxo Cleaner and Turpentine) so using the Workbench the player can craft one as long as they have the schematics.
 * Four pulse grenades and four pulse mines

Glitches

 * You can get to the higher level of the top floor by stacking barrels. However, it's very hard to do (you need at least 5 barrels) and there's nothing up there but an empty suitcase and an open safe, unless you want to just jump off the top which teleports you to the 4th floor - the same as if you go through Vault 87's Vault door.
 * You can get inside the bunker without getting the transcripts. To do so, walk into the corner made by the door and bunker access terminal. Then crouch, go into third person view, and twirl the camera around until it says "activate electrical switch". The trigger is very small, but should appear on the door or the door frame, a little higher than the player's head. Activate it, and the bunker door will open. This is a brilliant time saving method and should be used if you don't want to bother hunting down the transcripts.

Appearances
appears only in Fallout 3.

YouTube Videos
A faster way to open the Armory door WWf2XelJzOs