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The Arizona Spillway is part of the Hoover Dam, situated on the eastern side of the dam overlooking the Colorado River.


This facility forms an integral part of the Hoover Dam, providing the means to control the flow of water from Lake Mead into the river below. Sometime after the First Battle of Hoover Dam, the Battle of Arizona Spillway took place here, with the Legion pushing the NCR off of the east banks.[1]


Arizona Spillway is mentioned in the Fallout: New Vegas Official Game Guide Collector's Edition and appears in Fallout: New Vegas. The location also appears on an early map of Fallout: New Vegas[2] and a map of the Hoover Dam seen in-game.[3]

Behind the scenes

  • The Arizona Spillway is based on the real world location of the Arizona Spillway, located on the eastern side of the Hoover Dam in the state of Arizona.
Cut content
Spare Us the Cutter

There's an unused/deleted empty map called "Arizona Spillway Tunnel" (HooverDamIntArizonaSpillway). The Arizona Spillway is a real part of Hoover Dam, and at one end features a long cylindrical tunnel that drains off excess water. Presumably at one point you would have to go in there to fight the Legion (who are said to be gaining entrance to the damn through drainage tunnels). This is probably the large tunnel underneath the bridge to the Legion camp (much easier to see if you clip there BEFORE the endgame fight where it is covered over). The spillway is specifically indicated in the official strategy guide. It is indeed the big pipe/ditch area which has a bridge over it by the endgame. If you look under the bridge there is a large grating, as well as a small hatch, either of which may have lead to the deleted map. Possibly this was where the player would have originally emerged from after pushing the Legion out of the inside of the dam? It's also where the game lore says the NCR were pushed back off the East side of the dam before shoring up the defences on the dam proper leading to the stalemate at the start of the game. It was clearly an important location at one point (see also Cass' cut dialogue relating to it), but for whatever reason it seems it was excised fairly early on in development.



  1. Fallout: New Vegas Official Game Guide Collector's Edition pp. 372-376: [3.33] Hoover Dam
    All of the Main Quest in Act III centers around this location, as do the Main Quests involving the visit of President Aaron Kimball. A stronghold of extreme strategic importance for centuries, this location has seen recent turmoil between major Faction too. A few years before current events, Caesar's Legion rolled in, led by ex-Mormon missionary Joshua Graham, Caesar's Legate. Not considering NCR's army to be a serious threat, Graham exercised somewhat lax control over the Legion. During the Battle of Hoover Dam, NCR Rangers and Sharpshooters from First Recon employed risky tactics against the Legion with the help of the enlisted Troopers, and despite horrific loss of life, Caesar's forces were pushed back, but not routed."
    "The NCR has been holding the dam continuously since, and have fortified positions along the dam and up and down the west side of the Colorado River. Recently, the Legion pushed the NCR off of the east side of the river at the Battle of Willow Beach (which destroyed an NCR military camp) and the Battle of Arizona Spillway. Day to day military operations at the dam are under the command of Colonel Moore. While troopers are active here, there are also a large number of civilian contractors who are trying to keep the dam running. They are of a secondary concern to Moore, who is preparing from for an impending attack by Caesar and a visit by President Kimball.
    (Fallout: New Vegas Official Game Guide Collector's Edition Tour of the Mojave Wasteland)
  2. Early map draft of Fallout: New Vegas
  3. Hoover Dam spillway map
FNV NCR Flag.png
Fo2 NCR Seal.png