The sealed sewers is an unmarked location in the Mojave Wasteland.
The sealed sewers are accessed from the central sewers. You must obtain the key called Luke's find, which is found on "Blind" Luke in a room in the Central Sewers or "Sweet" Jill in a room in the East central sewers.
The south part of map contains a room filled with several ghouls, including a feral ghoul reaver.
The sealed sewers appear only in Fallout: New Vegas.
ps3 xbox360 It's possible that your follower may get stuck in the entrance of the Sealed Sewer and refuse to move from their location. [verified]