Vault 75 Vault 75 is a Vault - Tec vault located in the Commonwealth in 2287 . Background . Located underneath Malden Middle School , this vault was presented to the public as a safe place for children in the school to take cover in the event of a nuclear war . When the bombs eventually fell in 2077 , every designated family with a student attending the school , along with the teachers , made it to the vault in time . Upon entering , the children were separated from their families and escorted to the atrium , while the adults were executed by security staff , under the guise they were receiving " orientation . " This act of murder coincided with the purpose of the vault , which was to enhance the gene pool of its selected residents to create stronger and more intelligent subjects . The surviving children were harshly tested mentally and physically - bordering on torture , and without regard for the survival of weaker individuals - as part of the experiment . They were raised learning about the horrors of " Uptopland , " a nickname for the wasteland , and were told that they would be strong enough to venture out into the wastes and help the suffering people upon graduation . If they were intelligent and physically well built , they were either " harvested " for their good genes when they turned eighteen , or those displaying good intelligence and obedience were recruited to the vault ' s science team after graduation . The others who were deemed insufficient to the vault ' s standards were killed upon reaching the age of eighteen after a ceremony " celebrating " their graduation . However , details found in the various terminals suggest that even those who were " graduated " were killed after harvesting . The mission of Vault 75 , above all , was the refinement of human genetics . At some point the vault was opened and emptied . Some internal log entries suggest there was a rebellion among the junior test subjects , aided by a " graduate " scientist . This is backed by the way the bodies are placed in the Vault , indicating a quick and merciless breakout . Whatever the case , in 2287 there are no residents remaining , and the vault is serving as a hidden Gunners stronghold . Layout . The entrance is a standard vault entrance , accessible through the Malden School basement door from the wasteland . An elevator will take the player character down into the actual vault . Entering the elevator will activate the quest Vault 75 . The entire vault is initially heavily populated with Gunners , although depending on the player character ' s choices in the endgame , other enemies will appear : Brotherhood of Steel forces will appear if the player completes the game with the Railroad or the Institute , whereas synth s will appear instead if the player sided with the Brotherhood of Steel or the Minutemen . The vault is divided in three sections , the common , lab and admin area . To access the lab and admin area key cards are necessary to unlock the security doors . Downstairs is a combat simulation room , where you can use the terminal to initiate a combat training game and record your score online . This room also contains the Gunner commander that has a lab access card needed to open up sealed lab doors in the vault . The admin section of the vault can be found deeper in the vault behind the sealed lab doors . Some of the doors that lead to the vault overseer room within this section require an admin access card , which can be acquired / looted from one of the enemies lurking within . Appearances . Vault 75 only appears in " Fallout 4 " . Bugs . It is possible that the quest does not trigger upon entering Vault 75 , therefore causing the key cards not to spawn and making the Science bobblehead unobtainable . This may be caused by a misc quest pointing to the chems stash in the vault . On PC this may be fixed by spawning the required keys ( and ) to allow further progress ; the quest may be added and completed automatically when leaving the vault or the quest may trigger when leaving the admin area and completed upon accessing the Overseer ' s terminal . This can also happen even if you got the " Search for Caps in Vault 75 " miscellaneous quest .