The northern sections of the sewers are part of the North Vegas square, inhabited by the poorest people of the wasteland who can't afford to live topside. They are a fairly complex maze of winding corridors and open spaces. There are three major areas here. The western end contains a single large chamber surrounded by the sewer chambers, which is used as a living space. From there there's a large drainage chamber leading south to the central sewers and two passageways west. The larger one leads to The Thorn, while the smaller one to Westside.
The other large section is in the southeast, consisting of one room filled with greasers under Greasy Johnny and a larger section of the sewers that contains more people forced to live below. The pipes here lead to the central sewers and to a small section in the south that also leads to the central section.
There are also three ladders leading out to the different parts of the Mojave. The westernmost leads just outside the H&H Tools Factory, the northern one deposits the player just outside Freeside, and the northeastern ladder leads to the Crimson Caravan Company.
North sewers appear only in Fallout: New Vegas.