There are a few outlying towns, mostly consisting of condenser farms and people who aren’t city-types. The team has visited some of these sites on it’s various runs, but none of them seem worth returning too.
One of the largest towns outside Mars City is Heliopolis, aka Little Memphis. Exile communities and factions out of favor, such as the schismatic Egyptians, make up the population of most of these larger settlements. The borders are easy to police and control, they can set up their own legal system, and the members of whatever group it is aren’t gradually siphoned off into city life.