Vault 101

Vault 101 is a location near Washington, D.C., northwest of Megaton and west of Springvale. It is the home of the Lone Wanderer until they leave to search for their father.

Background
The Vault 76 overseer was originally selected to be its first overseer, but she refused the position in order to stay in Appalachia. Vault 101 was supplied with most of the equipment it would need to function indefinitely, but the vault did not receive a G.E.C.K. Vault 101's inhabitants remain protected from the outside world, with the exception of occasionally having to deal with radroaches.

Several recreational activities take place in the vault. Birthday parties are thrown, such as the Lone Wanderer's in the cafeteria and Wally Mack's including playing "Hunt the mutant" in the atrium. A notice on the bulletin board within the cafeteria announces an annual cake bake-off. The upcoming year was advertised as only accepting bundt cakes.

"Founder's Day" is a holiday celebrated in the vault. Beatrice dedicated one of her poems to the event, although she mentions having trouble finding a word that rhymes with "overseer."

Survey teams
A previous overseer assembled a survey team led by Anne Palmer, visiting Megaton in February 2241. Before leaving, the team planned for their journey and theorized types of mutations they might encounter.

The survey team returned and analyzed their samples to see if the outside world was still dangerously irradiated or able to sustain life. They studied the giant ant they killed and decided to revise their survey plans in light of what they learned. Lewis and Agnes Taylor, two members of the survey team, remained in Megaton for a period of time to serve as liaisons and to continue surveys of the surrounding environments.

Overseer Almodovar
Alphonse Almodovar is the overseer when the Lone Wanderer is a child, and his daughter Amata was the Lone Wanderer's friend. The overseer presented the Lone Wanderer with a Pip-Boy at their 10th birthday party. He states that at this age, vault inhabitants become contributing members of the workforce. The overseer admits that the vault's genetic diversity is only able to sustain their numbers for a few more generations.

The overseer appointed Jonas Palmer to be James' assistant, and relied on Stanley Armstrong to maintain the water purifier. Children were educated by Edwin Brotch, who reported their G.O.A.T. exam results to the overseer. Students including Butch DeLoria, Wally Mack and Paul Hannon Jr. named their vault gang the "Tunnel Snakes."

Conflict
After James decided to leave the vault, radraoches attacked and violence erupted between the security force and the Lone Wanderer who was tasked with escaping. After the Lone Wanderer's departure, conflict continued in the vault between those who wish to leave and those who insist the inhabitants stay, culminating in Amata sending the Vault 101 emergency frequency in hopes of bringing the Lone Wanderer back to assist in the situation. The Enclave contacted the vault, requesting access, claiming they previously had access via a password that no longer worked. The overseer denied the request.

Layout
Vault 101 is divided into four sections, including the main entrance, overseer's tunnel, atrium/upper level, and the lower level. The sections are separated by doors, and stairways connect floors and levels within two of the sections. Levels and rooms are identified by signs.

There are two paths to the Capital Wasteland, including a direct path from the atrium and a hidden tunnel named the overseer's tunnel. The sections are not directly stacked upon each other. They are staggered with each section moving progressively more westward as the vault burrows deeper into the earth.

Main entrance
This section connects the Capital Wasteland to the vault.

Overseer's tunnel
This section connects the overseer's office (in atrium/upper level) with the main entrance.

Atrium/upper level
This atrium connects the main entrance to the lower level. It is divided into two sub-sections, the admin and the atrium. The atrium is located on the upper level of the Vault. Access to this room is by a stairway connecting the cafeteria to the atrium. Systems connect admin to the atrium. Rooms in the atrium are located on two floors - an upper and a lower floor. Rooms on the upper floor (dining/Mack living room) are inaccessible.

The atrium is the main room of the Vault and is used by Vault residents for large social gatherings and sports, such as one of Wally's birthday parties, where he and the other children played Hunt the Mutant. A notice in the cafeteria announces upcoming baseball games.

Rooms in admin are the overseer's office, reception room (Jonas Palmer is found dead here during Escape!), operations, security, and systems (Floyd Lewis dies here during "Escape!")

Lower level
This is the final section of the Vault. Though named the lower level, this section actually covers two levels: the lower level and the reactor. Rooms in the lower level are the clinic, classroom, diner, DeLoria apartment, classroom, restrooms, and the Lone Wanderer's apartment. Rooms on the reactor level are the generator and storage room (BB gun shooting range), filter room (water purifier), and the reactor room.

Maintenance department
This department is responsible for cleaning and maintaining the Vault. Jobs within this department include garbage burners, Pip-Boy programmers, waste management specialists, and jukebox technicians. Maintenance technicians wear utility jumpsuit and work boots. Technicians sometimes carry a wrench or another tool with them and a utility key.

Notable loot

 * Medicine bobblehead - In James' office, in the clinic.
 * Rock-It Launcher schematics and 300 caps - In James' office, behind an Average locked safe behind the framed verse.
 * Grognak the Barbarian - In the diner, from Amata. If not used during their party, it will be in the dresser before leaving the vault.
 * Stealth Boy - On returning to Vault 101, found on Steve Armstrong's corpse in the decontamination/security control station.
 * Pre-War toaster - Behind the counter in the diner.
 * Butch's toothpick - Carried by Butch during Trouble on the Homefront.
 * Modified utility jumpsuit - Given by Amata for completing Trouble on the Homefront peacefully.

Appearances
Vault 101 appears only in Fallout 3 and is mentioned in Fallout 4 and

Bugs

 * Closing the vault door manually using the exterior console will work normally during Escape. Approaching the tunnel exit will result in the Vault door reopening behind you exactly when it is supposed to close if you don't tamper with the console.
 * On the rocky overlook outside the entrance to the vault where Dogmeat is sent if disbanded as your companion, there is a chance that he will fall through the map and can no longer accompany you. This happens only when he is dismissed, not when traveling to the vault with him.