Reservation

The Reservation is a ghoul town somewhere in the American southwest. It is naturally highly radioactive. The ghouls are sick of being the underdogs of the wasteland, and they have a new leader who's going to stick it to the humans good. Firing radioactive artillery shells via Nuclear Nellie, the ghouls' bigass gun, into every town ought to clear those pesky humans out. Of course, Nellie isn't quite working right and the ghouls haven't figured out a way to move Nellie around easily....

Appearances in games
The Reservation did not appear nor was mentioned in any of the published games, but was one of the main locations in the cancelled Fallout 3 project by Black Isle codenamed Van Buren. It is not certain if it will appear in any future Fallout game, but it is known that Bethesda received all Van Buren design documents from Interplay and might re-use some of the background from them.