Lost Hills The Lost Hills is a pre - War government bunker in Southern California and the headquarters of the Brotherhood of Steel , located in the deserts west of Junktown and the Hub , directly southeast of the Mariposa Military Base . Mysterious and impenetrable , it is the subject of myths and legends among many wastelanders . Location . The Lost Hills base can be found four squares west and eight squares south of Vault 13 . Background . The Lost Hills bunker had been originally constructed to house members of the government of the United States . Although this facility was completed before the Great War ( 2077 ) , none of its intended inhabitants had actually managed to reach it . Eventually , the bunker was re - settled by the soldiers from the Mariposa Military Base commanded by Captain Roger Maxson in an event called the Exodus . Maxson and his men were originally serving as a security detail for scientists working on FEV . Having discovered the atrocities performed in the name of science during FEV research , they executed all the scientists and declared themselves to be in full desertion from the US Army . Three days later , the Great War ended two hours after it started . After burying the scientists in the wastes outside of Mariposa , the soldiers sealed the military base , then headed out into the desert , taking supplies and weapon schematics with them . In November 2077 , the captain and his men , together with their families , had arrived at the Lost Hills , suffering many casualties along the way , including Maxson ' s wife ( but not his teenage son ) . The Lost Hills bunker became the headquarters of the newly formed Brotherhood of Steel . The installation was renovated and maintained by the Brotherhood for years , as they steadily gathered technology to preserve and research . After the events of " Fallout " ( 2161 – 2162 ) , the installation became a major research and development house , staying out of the politics of New California and aiding the newly formed NCR , eventually becoming the heart of an autonomous state , Maxson . Layout . Lost Hills was a pre - War government security bunker . Located almost entirely underground , the only indication of the presence of this installation was a small , reinforced structure containing the primary access elevator . After the Brotherhood seized the location , two sentries in power armor stood guard at the entrance at all times . One , a man named Cabbot , begins the become an initiate quest . Guard patrols in power armor routinely patrol the area around the bunker and the surrounding wastes . An encounter with them will usually result in thorough questioning and likely temporary arrest for trespassing on their land . Level 1 . The first underground level contains the main supply room ( filled to the brim with pre - War technology ) . The stockpile , while full of technology , is rather limited - every brother can withdraw only a single set of armor , while higher tier weapons are given only to those with special clearances from Senior Paladin Talus ( or another high ranking officer ) . Opposite the storeroom is the training chamber , where initiates exercise and learn combat skills under the careful guidance of the best fighters of the Brotherhood . The head instructor has his quarters located near the training room . Two other facilities are also present on the level - Head Paladin Rhombus ' s office and quarters and the guardroom , where surface guards spend their time when off - duty . Level 2 . Level 2 houses the living quarters for initiates , their classroom and the facility ' s medical lab . The youngest members of the organization spend their time here , studying to become either a Knight or Scribe , under the watchful eyes of higher ranking members . Their quarters are quite cramped - up to twelve initiates share a room ( or even more , if hot bunking is used ) , but fitted with all the necessary amenities . The infirmary is well stocked with medical supplies and in 2161 it offered the best medical treatment across the entirety of New California . Apart from healing injuries and removing radiation and addictions for free , the Brotherhood ' s medical staff can perform human augmentation surgeries : Level 3 . Arguably the heart of the Brotherhood , level 3 houses the most important facilities - workshops , where technology is maintained and recreated by Knights and the libraries , where Scribes patiently study old blueprints and knowledge , preserving it for future generations . Their living quarters are also located on this level , design as spartan as the ones of the Initiates , although less cramped - only three persons are quartered per room . In 2161 , Master Scribe Vree spends a lot of her time in the libraries , researching vital subjects for the Brotherhood . Even her quarters are located in the library itself . Level 4 . Housing the command center , mainframe and the Elders ' quarters , if level 3 is to be considered the heart , level 4 is the brain of the Brotherhood . Unlike other members , the leaders of the Brotherhood each have their own quarters , sparsely furnished , ascetic even . Their conference room is located at the back of the auditorium , used often , despite their apparent inability to agree on anything ( except that there ' s four of them , although even that was questioned ) . The mainframe , processing and storage containing the collective knowledge of the Brotherhood , is located out of the way , behind the quarters , accessed through an airlock . Interestingly , it isn ' t guarded by anyone , unlike the Elders ' quarters and meeting room . Inhabitants . The denizens of Lost Hills are exclusively Brotherhood of Steel members , with only merchants and other essential contractors allowed inside for their services . Discipline is strictly maintained , and everyone is expected to fulfill their duties . While strict , it ' s also a fair society - brothers are treated equally , expected to respect other castes and , while highly disciplined , allowed room for friendship , camaraderie and romance . Equipment - wise , castes can be easily identified : Things to do . As with all the other locations , there are quite a few things to do in the bunker : Originally , Lost Hills was not a bunker - it was a small concrete building , found by soldiers from Mariposa that employed it as a base , and slowly , but steadily changed it into a true fortress . More information is in the original . Behind the scenes . The Brotherhood also had an invasion ending planned , where the super mutants march against the Brotherhood and lay siege to Lost Hills . While defending their fortress valiantly , a traitor , Kedrick , would assassinate the Elders and sell the Brothers to the super mutants . Lost Hills would be subsequently destroyed . An unused " Dead Brotherhood " map is still included in the game files and can be accessed via the main menu . Other cut elements include a few non - player characters ( notably a scribe mourning the Brotherhood ' s reluctance to explore " soft " sciences such as sociology or psychology ) , a romance subplot including Jennifer , the Paladin , another Michael - related subquest about pulse grenades and girls from lower levels and a day / night cycle in the bunker .