Denver was a wreck. It was in the middle of a building boom shortly before the war, as many new jobs were opening there the city was swollen to bursting. Most of the construction was housing for these immigrants. When the war with China started, resource rationing occurred and suddenly the construction workers didn't have anything to build with and weren't getting paid. Union riots and strikes occurred because the city couldn't pay and the federal government wouldn't step in to help.
When Mexico and the Great Midwest Commonwealth started to suffer food shortages, Denver was hit hard because of its high population. Food rationing began. Food riots started because of the rationing, and some buildings were set on fire. The National Guard was called in to contain the rioting, using InstaPens (aka "bullpens") to contain and imprison rioters. Some people deliberately attacked police and National Guard troops so they would be imprisoned and fed. Rioters, National Guard personnel who disobeyed orders, and other military folk who refused to help contain the riots were sent west and east.
Then, an outbreak of the New Plague hit the city. Rioters burned down large parts of the city in their fear of contamination and anger at their treatment. Many panicked and fled the city by car, clogging the freeways when they ran out of gas and trapping everyone behind them. (Though this is debatable considering the restriction of use of fossil fuels and the war with China over the last oil. It is however possible that there were still a few people who were willing to pay large amounts for little fuel rather than the $200,000 needed to buy a nuclear generated vehicle.) And then the bombs fell, destroying some of what was left and killing everyone who had managed to live through everything else.
Post-War, Denver has been abandoned by civilized folk, mainly because of lingering radiation (which is gone by now) and huge packs of wild dogs that have taken over the city. Small groups of scavengers have holed up here from time to time or tried to loot some of the buildings but it has never been a concerted effort until now.
The Hangdogs were formerly the most prominent faction in the region, until they were defeated by Caesar's Legion and assimilated in their ranks. Hangdogs who desired freedom fled their former base at Denver Zoo and took up a new one at CommonGround Golf Course, rebranding as 'Dog Lords.' They see the Hangdogs who joined the legion as tainted and unworthy and their mongrels to be tainted but salvageable, unlike their human masters.
The Dog Lords own approximately half of the territory, due to them being good at fending off the feral dogs in the street, they have little trouble navigating them. However, they have one rival faction who stand in their way from taking over the entire city, the Copper Toes.
The Copper Toes arrived three years after the Dog Lords began their campaign, they're a lot better equipped and organised than the Dog Lords but have fewer numbers. The Copper Toes mostly reside in Commerce City but have small pockets of territory around the city. Though the Copper Toes are far more civilized than their Dog Worshipping rivals, they are by no means benevolent to the community as they are just as ruthless and care very little about anyone who isn't their own.
There are one or two small settlements scattered around the territory, Omar's place is the most prominent, a large manor house which has since become a community, a small shanty town on the outskirts of the city. There are also several business men, such as Madam Patern, the Fortune Teller and Crazy Ed, the owner of a gunshop.
The Economy of Denver is incredibly unbalanced, the Copper Toes are responsible for most of the wealth in the region, though some credit can be offered to salvagers, the few that are able to survive the constant onslaught of feral dogs and raider attacks.
Hound Dog Radio is the only radio station operating in the region, it's location is unknown to most and is buried in some sort of military bunker, hidden somewhere in the city. The DJ, Pierce, doesn't seem to support either of the two prominent factions in the region and urges civilized folk to stay away from them.