Vault 27

Vault 27 is one of the Vault-Tec Vaults. As part of the Vault Experiment, this Vault would be overcrowded deliberately. 2000 people would be assigned to enter, double the total sustainable amount. The location of this Vault is unknown. It can be assumed that the vault failed from food and/or water shortages and//or disease from the overcrowding.

Appearances in games
This Vault does not appear in any game and is mentioned only in Fallout Bible.

It also should be noted that a group of a hundred or so ended up both dieing and the survivors of that group formed the Vipers.