Vault 39

 Vault 39 (also known as the Lone Star Vault or the old Abilene Vault ) is one of the Vault-Tec vaults, located in what was known as Abilene before the Great War and is now called Lone Star.

Background
The vault's original purpose in the vault experiment is unknown. Recently, due to Reese's experiments in the vault, it has become a veritable jungle with huge mutated plants that thrive there and will provide more than minor obstacles to overcome. 

Layout
The vault has three levels consisting of three medium to large maps. On the surface a broken-down shed sits next to the vault, in which a functioning car can be found.

Notable loot

 * A G.E.C.K. can be found on the third level, along with the key to the shed on the surface.
 * A map showing all key Brotherhood of Steel locations can be found on the third level.

Related quests
The player character would have had to fight their way through the mutant plants as the ecology desperately tried to kill them. Once at the third level, they would have found a G.E.C.K. and a key. On a desk, papers including bios on Banshee and the Jackals and a map showing the origin of the Nursery documenting Reese's movements southwards as well as his next destination, Austin, could be found. Using the key to drive the car away from Vault 39 would have ended Act II.

Appearances
Vault 39 was going to appear in the canceled Fallout: BOS 2.

Behind the scenes
The developers had hoped the car in the shed would be a '59 Volkswagen Bug.