The Compound is not located in Paradise, but is only 1.5 miles away from the town, as noted by the signs outside the tunnel to and from the Trainyard Area. The compound is formed by various buildings connected with each other, built around an open area. The only way to enter is from the left side. Within the compound, there are several storages, some of which have weapons, explosives and flammable substances. There is also a chapel, a kitchen, a basketball arena, and Uncle Dave's bedroom. On the pathway from the tunnel to the Trainyard Area to the building, there is a sign that reads "Attain the Glory of Heaven the quick and easy way", and inside the compound there are several posters with distorted religious content, such as one featuring Baby Jesus firing a weapon and says "Baby Jesus says: Bullets are the seeds of Victory. Save Ammunition = Saved Lives".
The Compound is first accessible Friday, during Uncle Dave's birthday. The Postal Dude wants to give him a Birthday Gift, so he proceeds to go to the Compound, where, as the Dude notes, Uncle Dave usually throws "nice parties". The nice party is revealed to be under siege by the ATF. Almost all news in the Paradise Times edition of Friday are about the siege, except the main title which is about the spree murderer's killings (implied to be the Postal Dude himself). The ATF has placed agents in strategic positions, atop various hills and rocks. There are police cars and dogs on the way to the compound, and even tanks and APCs around the building. The zealots have hung several posters in the walls, including one that says "ATF we fucked your wives" and even one dedicated to Lieberman.
When the Postal Dude arrives, the ATF is telling the cult to stay inside the building, douse themselves with something flammable and gather in a confined space. Uncle Dave and a female zealot come to the roof and begin a discussion with the ATF. Uncle Dave tells the ATF that he and his cult are only "innocent bystanders", but later states that the "Good Book" has told him to make the ATF agents die and then kill himself. The ATF commander arrives and orders his agents to neutralize the situation. One of the ATF agents using a Napalm Launcher fires some napalm towards the building, and the zealots accompanying Uncle Dave start shooting. The ATF commander then proceeds to order his agents to "comb the perimeter".
The Postal Dude will get a "Wanted" status since he arrives to the pathway from the Trainyard Area to the main building, even if he is unarmed, so he must face the ATF agents and dogs from that point. Once he enters the building, the zealots are seen heavily armed and taking defensive positions. The Postal Dude finds Uncle Dave in his bedroom, dancing with some zealots, and and gives him his Birthday gift. In that very same moment, the ATF finally manages to break into the building, and begins a massive gun battle against the cult. Some agents arrive to Uncle Dave's bedroom and attack him and the Postal Dude. To get out of the compound, the Postal Dude must face a large team of ATF agents. Since the entrance to the building has been blocked because the ceiling has collapsed, the Postal Dude must escape through a window. Once outside the building, the Postal Dude must face more ATF agents who are atop hills, and all over the way back to Paradise. The ATF commander arrives last with a Rocket Launcher, blocking the exit to the Trainyard Area.
In the Postal film, the Compound is also home to the cult. However, the whole plot of the siege of the compound by the ATF is absent. The compound has an underground bunker, in which the cult and the Postal Dude take shelter when the place is invaded by Terrorists. Uncle Dave's right-hand man Richard shoots and kills him in the bunker, and later imprisons the Postal Dude there.
- The Compound is based on the real Mount Carmel Center, which was the Branch Davidian home. The place was destroyed during the 1993 Waco Siege, which resulted in the dead of over 70 Branch Davidians and 4 ATF agents.
- Uncle Dave's Compound is 10 miles away from Nogales, 33 from Willcox, 55 from Tucson, 113 from Las Cruces, 160 from Phoenix, and 381 from El Paso.
- The sign "OJ we understand" is a reference to the OJ Simpson case and possibly to the Rodney King police beating, the Branch Davidians had a likewise sign "Rodney King we understand".