The sewers consist of a labyrinth of tunnels hosting a giant rat infestation, roaming packs of feral ghouls, and Fiends gang members. Certain sections of the sewer system are inhabited by vagrants who have retreated from the city above.
Living in the underbelly of New Vegas, many survive by hunting rats for food and gambling on the fights at the Thorn. Others are prospectors who make journeys into the unsafe parts of the sewers. Most of these people speak to the player character in depressed tones and occasionally warn of the Fiends taking over parts of the sewer system.
The New Vegas sewers appear only in Fallout: New Vegas.