Guard Houses

Guard Houses are located in each district, similar to the idea of police stations. If someone has trouble and needs help from a guard, they would go to the nearest guard house. If someone is being brought in for questioning, they are brought to the guard house. Each guard house would have a section of holding cells where they could hold prisoners until they are able to be taken to the Skeleton Isle Prison. The size and number would depend on the district and the sort of trouble they run into.
The guard houses also serve as a "home base" for the guards of the city. Although technically the city guards all work together, they are each assigned to a guard house and wear a badge that indicates which guard house they work out of. It is rare for a guard to be assigned to a patrol outside of the district that their guard house is located in, with the exception being large events where a district may request additional support. Most of the guards live in the district they work in, although this is not a requirement, and become very familiar with the people and locations within that district. They typically know all of the back streets, the different twists and turns, of their assigned district and feel uncomfortable when asked to work outside of it.