The first settlers, Mormon missionaries, arrived on June 14, 1855 and selected a site, along one of the creeks that flowed from the Las Vegas springs, on which they would build the fort. The fort served as the mid point on the trail from Salt Lake City, Utah and Los Angeles, California. During the Utah War, the Mormons that occupied the Fort abandoned it leaving it destitute.
By 2281, the Fort had survived the Great War and is now serves as the headquarters for the Followers of the Apocalypse in the New Vegas area.
The Old Mormon Fort consists of a courtyard filled with tents and non-player characters. There are two sections within the walls of the fort, one in the western and another in the eastern corner of the courtyard:
Upon entering there are two Followers guards behind a sandbag wall in front of a flagpole flying the Followers of the Apocalypse flag. There are six tents in total within the courtyard.
The one in the western corner of the fort contains four beds and a chair. Three of the beds are occupied by Wayne, Farris, and Roy.
The southwestern tent contains two bunk beds, two empty shelves, two chairs, and a table. Arcade Gannon is usually found within this tent. If he is not there, he can likely be found in the courtyard.
The tent in the southern corner contains five oil drums and two large wooden crates.
The tent in the eastern corner has three bunk beds, one round table, two chairs, an empty shelf, and one table. There are two gamblers found sleeping in this tent, and sometimes various non-player characters will sleep in the remaining bed. There is also a Followers Doctor outside of this tent.
The northeastern tent contains two bunk beds, two empty shelves, two chairs, and a table.
The southeastern tent contains three bunk beds, one round table, two chairs, an empty shelf, and one table. Followers guards will sleep in the beds of this tent, and a Follower's doctor can be found within this tent as well
This guardhouse is directly to your right as you enter the fort.
When you enter the guardhouse, there will be a small medical area directly in front of you with nothing of note besides a filing cabinet with one bottle cap inside. To your left are the stairs leading up into a bedroom. On top of the bookshelf is the Old Mormon Fort Snow Globe. There is also a Today's Physician magazine on top of the desk, which is considered owned and must be stolen.
This guardhouse serves only as storage for the Followers' as evident by the abundance of wooden crates. The only items you can take are the tin cans on the second floor.
The Old Mormon fort is a real building in present day Las Vegas. In fact, it is the first structure built by European immigrants in Las Vegas. Constructed in 1855 by Mormon settlers of European descent, it would shape the city of Las Vegas, Nevada, 50 years later.
There's a peculiar dead body in the alleyway near Genaro down the side of the Mormon Fort. There's nothing obviously interesting about it - it's just a generic npc with some clothes and food. what's slightly more interesting is its name VFSAlleyCorpse01 and designation as "Dead Squatter" ingame. This corpse is always disabled and to be honest I get the feeling that it seems like it might have been part of some abandoned quest. Even more peculiarly the official strategy guide deliberately draws attention to it (page 335) and advises you to loot it!
There are unused placeholder "Bark" topics (i.e. things they randomly say to each other/the player) for the Followers and their guards listed as "VFSFollowersBarks". No actual dialogue exists, so possibly this is just a leftover before the real dialogue was moved to its appropriate quest.
The sleeping "patients" in the Followers fort are drawn from the Gambler pool of NPCs. However, there are also three pre created NPcs with the same name that were presumably going to be used instead at one point. They are all elderly characters. VFSFollowersSleeper1-3. They're also set to respawn, whereas the ones used in the game are not.
Occasionally the main entrance gate will appear open from the outside of the fort, looking inside you will see the landscape that makes up the interior of the fort, but it will be completely devoid of all people, items and tents, only the ground and the walls will show.
Julie Farkas will have an endless supply of skill magazines for sale if you exploit a dialogue bug that is covered in the discussion section on this page.
Sometimes the followers will randomly attack you, even if you have a high reputation with them.
While having the minigun equipped, if you begin to shoot at the follower, it will cause your character to look like his hands are attached to the ground.
Occasionally when you walk into the fort, one of the Followers' guards will have dark skin from the neck up, but be very pale from the shoulders down. Though it's easy to miss on pale skinned NPCs, this bug has been noticed on several guards. The head and body skins are often mismatched
↑Fallout: New Vegas Official Game Guide Collector's Edition p.329-330: "[2C.01] Old Mormon Fort At the north end of Freeside, an Old Mormon Fort has been converted into the base of operations for the Followers of the Apocalypse, a quasi-religious organization hellbent on helping humanity, while ensuring nothing like the Great War ever occurs again. The courtyard of the fort is used for general triage and care, with the old (heavily damaged) adobe fort buildings themselves being for Followers' storage and residences. Despite the historic name of the place, there are no serious fortifications–just fences and gates with a few armed Followers inside." (Fallout: New Vegas Official Game Guide Collector's Edition Tour of the Mojave Wasteland)