Jefferson Houses isn't an actual place. It's just going to be a placeholder page for the small slum houses located in the Jefferson neighborhood, located near Jefferson Heights.
All the houses follow a uniform design, much similar to this ghetto house. For example, they all are built with brown brick with grey shingle roofs. They all have driveways to the left of the house. Some of them have single-car detatched garages.
Maybe one of them can have an interior for a mission or something? Could be a thought, like a meth lab or something like that.