The Vault - Fallout Wiki

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The Vault - Fallout Wiki
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Fallout: New Vegas locations project
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X-66 hexcrete archipelago
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Map MarkerX-66 Hexcrete Archipelago
Cell NameNVDLC03SLHex
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The X-66 Hexcrete Archipelago is a location in Big MT in 2281.


Hexcrete was intended as a revolutionary construction method and material that didn't quite end up being revolutionary after repeated tests. The hexcrete towers at Big MT are all that remains of this once great research project.[1]


It is directly north of the Z-38 lightwave dynamics research station, south east of the X-13 testing facility and west of Z-43 Innovative Toxins plant.

It is made up of large hexagonal prisms sticking upright from the ground, ranging in height from shorter than the player to several stories tall. There is also a pool of mildly radioactive liquid in the center which radiates one rad/second. Two packs of night stalkers spawn to the south and east, in range to attack any player. These night stalkers can be accompanied by multiple Y-17 trauma override harnesses. Also, it's proximity to the X-13 research facility means that any robo-scorpions guarding it will attack you if you venture north from this location.


  • There does not appear to be any entrance to the structure or purpose for the location other than a fast travel point.
  • The pipes surrounding the area are riddled with frag mines. Caution should be taken if deciding to walk across them.

Behind the scenes

  • The hexcrete was inspired by a concrete plate structure seen in Fallout 3.[1]
  • There is a scrapped ending in the game's files where Goodsprings was crushed by, "mysterious hexagonal shapes from the sky."


The X-66 Hexcrete Archipelago appears only in the Fallout: New Vegas add-on Old World Blues.


  1. 1.0 1.1 Chris Avellone responding to a Vault admin via e-mail: "Hexcrete: Intended as "revolutionary" construction method and material that didn't pan out to be revolutionary after repeated tests. The idea was modeled after the concrete plate structure seen in Washington D.C. in Fallout 3 - the hexcrete towers are more simple versions of mass-production efforts."