Millhaven

"Whiskey Deltas capable of jumping heights of thirty feet or more. The walls of this compound are twenty feet Lt. Mora. If I didn't know better, I would say your report was tailor made to foster dissention in my ranks."

- Major Everly

Millhaven is a military outpost first mentioned in the Left 4 Dead comic The Sacrifice, based on the DLC campaign of the same name. Bill, Zoey, Francis and Louis are taken to Millhaven after they are rescued by the Military at the farmhouse.

Once they arrived, the Survivors are woken up and ordered at gunpoint to leave their weapons behind and are marched out of the rescue vehicle where they are met with aggressive military personnel who immediately did not get along with Francis and threatened to shoot anybody who tries to run away. A military personnel tells them that they are going to "testing" which is a series of tests run by a doctor to see if people are Carriers which Zoey reacts to nervously. The military locked Francis and Louis up in a cell together and sends Zoey and Bill to a doctor.

The military personnel guarding Louis and Francis's cell asked them what they saw since they've been fighting &quot;Whiskey Deltas&quot; or &quot;Walking Dead&quot; for two weeks and wanted to know if the Infected are mutating. It is confirmed that they don't know anything about the Special Infected and the commander of the outpost doesn't believe in the abilities that they have or even of Special Infected at all. Meanwhile, Zoey and Bill are being tested by a doctor to see if they are Carriers which all four apparently are. The doctor decides to help Bill and Zoey escape while the two guards helped Francis and Louis escape after a close encounter with a wandering Witch. They also encountered all of the Special Infected (excluding Left 4 Dead 2 Specials) and the Horde. In Part 3, most (or all) of the Millhaven staff is killed.

In The Parish in Left 4 Dead 2, it is stated that the Military is killing any Carriers of the Infection off. This might explain the large amount of dead bodies outside the outpost unless they are the Infected. However, in The Sacrifice comic, it seems that the military is simply trying to contain the Carriers so they could not infect others while testing them to try and get a cure to the Infection.

Staff at Millhaven

 * Major Everly ― the commander of the outpost. Concerned with keeping the base going and refuses to believe the reports of Special Infected. Forcefully relieved of command in Part Two. He rallies the loyalists to attempt an escape but is killed when a Tank (the same one that killed Mora a few moments ago) blew his helicopter up just as it takes off. There is a possibility that he actually knew the truth, but was trying to prevent panic from being spread or was under orders to not reveal anything, due to his unusually calm demeanor as he is being overthrown though this is unverifiable due to his death (confirmed dead).
 * Lt. Mora ― second in command; paranoid of Carriers; relieves Major Everly of command with force due to his concern over the base's safety. He is "left for dead" after an Infected manages to claw his protective mask off, infecting him in the process. His team refuses to pull him back up to higher ground and he is left to fight alone. In the process of becoming an Infected, he encounters the Survivors and attempts to kill them. Bill quickly punches him to the ground right before a Tank (the same one that destroyed Maj Everly's chopper a few moments later) arrives and decapitates him (confirmed dead).
 * Sergeant Downey ― Lt. Mora's confidant and fellow soldier, who didn't agree that carriers had to be killed on sight along with the infected and thus was not recruited into the mutiny (presumed left the base before the mutiny against Major Everly and the subsequent infected attack and thus survived).
 * Sergeant Hendricks ― part of Lt. Mora's squad who was ignoring orders from and mutinying against Major Everly, Sergeant Hendricks refuses to help Lt. Mora after his commanding officer lost his gas mask and was exposed to the Infected (presumed one of the few survivors along with his squad).
 * Soldier Jeff ― partnered with Annie, guarding the room holding Francis and Louis. Teams up with the two Survivors in the half of Part Two. Noted with a purple speech bubble when talking in the comic. Leaves the team to rejoin a holdout area in Part Three, but it was overrun by the Infected and he either died in the fighting or was overwhelmed trying to escape (presumed dead).
 * Soldier Annie ― partnered with Jeff and also guarding Francis and Louis. Teams up with the two Survivors and takes them to the armory―noted with a red speech bubble when talking in the comic. Leaves the team to rejoin a holdout area in Part Three, but it was overrun by the Infected. She was last seen as the female soldier being attacked by the Infected at the end of Part 3 (presumed dead).
 * Soldier Pena ― with Lt. Mora's mutineers and part of Sgt Hendricks' squad (presumed one of the few survivors along with Sgt Hendricks).
 * Soldier Brooks ― with Lt. Mora's mutineers and part of Sgt Hendricks' squad (presumed one of the few survivors along with Sgt Hendricks).
 * Soldier Davis ― with Lt. Mora's mutineers and part of Sgt Hendricks' squad (presumed one of the few survivors along with Sgt Hendricks).
 * Soldier Rivera ― threatens Zoey into giving a saliva sample, is disarmed and cowers from Zoey due to his fear of possible contamination from her―noted with a navy blue speech bubble when talking in the comic (With gas mask on). Going by his speech bubble color, he also seems to be the soldier who punches Francis and tells Zoey that they are going to be tested (presumed dead as either a paranoid murder or mercy kill by his comrades, or was left to die to the horde by those who managed to escape).
 * Unnamed Doctor ― in charge of making a cure for the Green Flu which stops Zoey and Bill from being executed as they become test subjects. Fears that there may not be any cure at all and tells the Survivors that they should escape together. He is killed by a Smoker while the Survivors attempted to escape from the complex with a stolen train (confirmed dead).
 * Nate ― wall guard, part of the mutineers. Told Jim to put his mask back on when he tries to smoke a cigarette and while Jim was talking got attacked by a Hunter (almost certainly dead).
 * Jim ― wall guard, part of the mutineers. Took his mask off to smoke a cigarette and when his back was turned his partner got attacked by a Hunter. While he was watching, a Smoker grabbed him (almost certainly dead).

There are other unnamed soldiers at the base (divided into mutineers following Lt Mora and loyalists to Maj Everly) who are promptly attacked by the Infected in the half of Part Two. One was killed by a Witch and another is seen who has turned into a Boomer and in the start of Part Three, a Smoker-soldier is also seen. Presumably, at least some of both sides besides Sergeant Downey (who is assumed to have left the base before the mutiny and thus was not involved in either the mutiny or the infected attack) and Sergeant Hendricks and his squad (who were among the mutineers, but left Mora to die after his gas mask was torn off and he was compromised, and are assumed to have made it to the vehicles and escaped) managed to either leave before the mutiny or escaped during the infected attack.