不過就跟所有烏托邦一樣，和平不可能一直持續下去。在2271到2281年之間的某天，羅伯特·豪斯打算佔據21號避難所。居民為了抵抗不被他的帝國吸收，同意用賭博的方式 解決這個問題。進行方式是用21點，幾乎整個避難所的居民都參加了。最後支持與豪斯帝國合併的居民以些微之差獲勝，然後21號避難所內部有用的電子零件和設備立刻被豪斯拆走，部分還被混凝土填滿，使的居民被迫到廢土上定居。在Sarah Weintraub和Michael Angelo(也就是Sheldon Weintraub)的堅持之下，豪斯保留了最上層的部份，並讓Weintraub姊弟在此經營一間旅館，這旅館之後也成為他新生帝國的收入來源之一。
The vault's main blast door has been transformed into a sign advertising the vault/casino. "Vault 21" is emblazoned on it in neon lights. The vault entrance is an above ground building which contains the Vault 21 gift shop. It is run by one of the only two native residents to have remained, Sarah. Stairs lead from the gift shop down into the vault.
The vault has been converted into a casino and hotel. There is a central atrium with gambling tables, a hallway with living quarters, including Sarah's room and a guest room that the player can rent. Another door leads to the cafeteria/diner. The lower levels were filled with concrete by Mr. House and are inaccessible except for the maintenance level, which is accessible from the basement of The Tops, where the Chairmen appear to have tried to break in. This level consists of a long hallway with a few small rooms branching off of it. The elevator in Benny's suite leading to it is locked unless he is attacked in the Tops Presidential suite, and the tunnel ends in another locked door.
- Snow globe - The Strip behind an average locked door in the northeast-most room (Sarah's room). In the same room, there is a hard-locked dresser beside the bed with 270 caps and several clothes.
- An oversized toy car and a sensor module can be found in the hotel lobby.
- Strip letter 1 and Strip letter 2 can be found in guest rooms in the south-east. Strip letter 3 can be found in the guest room just west of the inaccessible door to the south.
- Bye Bye Love
- The Finger of Suspicion
- Suits You, Sarah
- Tourist Traipse
- The background music is Serenity, which was originally used for Modoc in Fallout 2.
- If you have started The Finger of Suspicion, then there will be three Omerta thugs threatening Martina Groesbeck in one of the rooms.
- The Tops houses an elevator that goes down to the basement and connects via a blown open wall to the service areas of Vault 21. This elevator is normally locked and unable to be picked, but is automatically unlocked if Benny is given the chance to flee when confronting him at The Tops.
- There is a locked door at the end of a hallway in the vault that can be unlocked using console commands. An invisible part of the Vault will appear if you walk a little forward. There are no lights and this part ends-up with two staircases leading to nowhere.
- Although the theme of this vault revolves around gambling, and there are gaming tables around, it is not possible to gamble in this location.
- No doors in this vault feature a gold stripe and the number 21, but instead are all marked "No Access". The same is true for Vault 3.
- A picture showing James and Catherine (The parents of the Lone Wanderer from Fallout 3) can be found beside a bed in Sarah Weintraub's room, although their likeness simply seemed to be recycled for that photograph like other Fallout 3 assets were.
- The lights in the vault appear very dirty and rusted, and are actually the models seen in ruined vaults, such as Vault 34.
- The eastern billiards room contains a jukebox named "Jukey The Jukebox". Other than the name, it doesn't appear to be special in any way.
- If you leave items in the locker of your room and later get the reputation of "Wild Child" for The Strip, then you cannot rent the room or retrieve the items.
- Players may make this their personal vault/home once they are given a room by Sarah.
- Vault 21 is the only known vault that does not still possess its cog-shaped blast door. Instead, the door was converted in to a sign advertising the hotel.
- Oddly enough, the current entrance to Vault 21 leads all the way to the gift shop without any apparent modifications. This would mean that, unless the current access stairs were added for the vault's hotel conversion, the gear door and entrance chamber were entirely above ground.
- If you look to the right when you walk in, you will see Vault 101's bulletins on the wall with only a couple of changes made to it, such as the Vault 101 bake off ad being changed to Vault 21.
- There is a working light switch in the player's hotel room.
- The sub-basement hallway tunnel appears incomplete when seen in the GECK, there's also a door that supposedly leads to the hallway, but it's blocked by a large chunk piece.
- There is a slightly undersized terminal in the gift shop.
Vault 21 appears only in Fallout: New Vegas.
Behind the scenes
- Vault 21 was designed by Jorge Salgado.
- Vault 21 is a reference to the card game "Blackjack", where 21 is the highest sum and its limit, usually declaring an instant victory. This supports its gambling theme. 21 is also the minimum legal age a person must be in order to drink and gamble, therefore reinforcing the main theme.
- Vault 21's lower levels being filled with concrete is a subtle reference to the Silver Slipper Casino, as it was rumored that the mechanized slipper at the front of the casino was filled with concrete by Howard Hughes, the man who was the basis for Mr. House.
- James Garcia created the 3D model of the neon sign letters.
- The computer in Sarah Weintraub's room contains an email from a Charlene Tann who mentions her husband Biff Tann. This may be a reference to the Back to the Future trilogy, in which the antagonist is named Biff Tannen.
- Has platform::PC If you take the tour with Sarah Weintraub, your companions may disappear and not reappear when you exit the vault.[已核实]
- Has platform::PC Sarah may not recognize Vault 21 jumpsuits as vault gear, but will trade for them normally at the usual price.[已核实]
- Has platform::Xbox 360 Sometimes when you take the tour with Sarah Weintraub, she will walk with you out of the gift shop and then stay still above the stairs leading to the hotel part of Vault 21 and will be unable to talk to.[已核实]
- Has platform::Xbox 360 Vault 21 has a high probability of causing the game to freeze during loading screens.[已核实]
- James Garcia's portfolio
- Vault 21 terminal entries#Your hotel rocks