In the pre-war world, Union City was a small desert town facilitating the trucking industry along Interstate 15. Before the Great War, the town and all other properties in the Pass were bought by Athens-Tec to furnish the company's workers. For unknown reasons, an inedible, highly explosive genetically modified form of corn designed for high-yield ethanol was grown in the surrounding farmland.
Despite being close to several US military missile bases, Union City escaped the devastation that destroyed Los Angeles and San Bernadino proper relatively unscathed, but was still victim to the lethal radiation and airborne FEV-II that ravaged California. Like much of the Cajon Pass, the soil was unable to support any other crops besides the modified corn; as a result, Union City became just another of the abandoned ghost towns that littered the desert.
As the Survivalist Raiders expanded out into the Pass, they re-occupied Union City and used it as a slave settlement, continuing to cultivate the mutant corn. However, they quickly realized its relative uselessness as a food source and resorted to only using it for crude explosives.
As hostilities grew between the Cajon Pass and the Survivalists, the NCR - spurred by corporate interests in the GMO corn as a potential cheap source of fuel - took over Union City and converted it into a frontier outpost and military strongpoint, repairing the town's power and water infrastructure and fortifying it with a sandcrete wall. NCR sharecroppers moved in to grow the GMO corn, but despite the NCR's efforts to further modify it, it proved useless as cheap source of ethanol.
Union City is a large, well-fortified NCR town composed of primarily sandcrete dwellings and a handful of restored or re-utilized pre-war structures. The town forms the Eastern boundary of the worldmap; its own boundary is marked by large Ethanol Fields to the North of the city, and a ruined pre-war Missile Base to the South.
From the Main Gate, the road leads West; to the immediate south of the gate can be found NCR military barracks and medical tents, as well as the Union City Clinic. North of the gate is the town gallows. Going west is the main drag, with the Shi Bank, Mojave Express and Gun Runners on the northern side, and the Ram Shackle Bar on the southern side. The road intersects with another leading North-South, lined by numerous sandcrete NCR homes. Up the hill further to the west can be found the NCR Territorial HQ. This road passes by a large pre-war truck refueling station on the east side and Molly's Bar on the west side, before ending at a few ruined houses. Going north are numerous NCR homes, until the road passes the El Rey Motel and continues on to the Ethanol Fields, in the middle of which lies Doc Marius' "Fortress of Solitude" at the Radian-Helix Media Studio. To the East of Union City, at the base of the mountains, a large train track and adjoining station run North to South.