Denver is one of the only cities which boasts a high percentage - though still under 50% - of people not infected by the Flare. It is located in Colorado and appears in The Death Cure. Here, normal live seems to take it's course, with shopping malls, cabs and coffee shops. But the inhabitants seem to be frightened, avoiding any contact with others and protecting themselves with masks.
Denver has an extremely high level of strict security, with Red Shirts often patrolling the streets to discover newly-infected people. Thomas once watches a customer in a coffee shop who has apparently taken the Bliss. Red Shirts found him and finally brought him to the city's Crank Palace. There are also bounty hunters looking for Immunes to be sold to WICKED.
The city eventually caved in to the Flare after the infected finally outnumbered the healthy and hundreds of Cranks broke out of the Crank Palace and invaded and took over the city.