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Federal Surveillance Center K-21B, located underneath an abandoned shack, is a location in the Commonwealth in 2287.


Federal Surveillance Center K-21B was an underground surveillance facility used by the government before the Great War; it is now north of the impact crater in the Glowing Sea. The bunker was intended to serve as an outpost for government surveillance workers, who were to continue their work after the bombs fell. However, few workers made it to the facility; a holotape recorded by an employee named Jeff Buzensky details the death of his coworker Bill Stevens, who was only a few steps away from the trap door entrance when the bomb struck after leaving to retrieve some personal effects from his vehicle. The bunker was not stocked with enough food due to budget cuts, and its inhabitants eventually died of starvation.[1]


An armor workbench and a few nuclear waste barrels are on the porch of the shack. The shack itself contains a Novice-locked trap door in the floor next to a skeleton and Bill's suitcase. Through the trap door is the bunker comprising the three-level underground facility, with an open shaft passing through the middle. Up to three synths inhabit the interior, one of which is a synth leader.

On the lowest level is a power armor station under the stairs, as well as a trunk and an Advanced-locked safe to either side of the Novice-locked mainframe terminal. The terminal can be used to reboot the system and reactivate the elevator across the room leading back to the surface south of the shack. However, activating the elevator will also enable two hostile Protectrons, which cannot actually be disabled using the terminal.

Notable loot


  • The interior of the bunker does not respawn.
  • The map marker changes from "Abandoned Shack" to "Federal Surveillance Center K-21B" after using the elevator to leave the bunker.
  • If the player character is friendly with the Institute upon first entering the bunker, the synths will be allied and will not attack the player character. The synths will speak using the same dialogue as those found in the Institute and elsewhere in the Commonwealth.
  • There are only three actual "radios" in the bunker, with one on a desk in the northern room on the middle level and two on desks on the lowest level. The other radio objects in the facility are labeled "surveillance device," and emit only static.

Companion comments

  • When at this location, companions make comments, which are activated at the gantry overlook.
Location comments
Character Comment
Cait "Interestin'. More to this place than meets the eye."
Codsworth "Ah a secret, underground base! Right out of the ol' spy novel, wouldn't you say, sir/mum?"
Curie "Look at all that. We should go into all the shacks now."
Danse "I've heard of these places. Civilian on the outside... military on the inside."
Deacon "I think what we have here is a failure of intelligence. Would've been good to know about this."
John Hancock "Roomier than it looks."
Nick Valentine "Well, could've fooled me."
Piper Wright "How far down does this place go?"
Preston Garvey "Woah. A lot bigger than it looked on the outside."
Robert MacCready "Well, well. Looks like we stumbled into an old government dirty little secret."
X6-88 "An old surveillance center. It could have been concealed better."


Federal Surveillance Center K-21B only appears in Fallout 4.



  1. Fallout 4 Vault Dweller's Survival Guide Collector's Edition p. 360: "[5.18] ABANDONED SHACK
    Warning! Extreme radiation danger! An unassuming shack has a federal survival installation (codenamed K-21B) hidden beneath it. Enter the shack and open the trapdoor (Novice) or use the key in Bill the skeleton’s suitcase."
    (Fallout 4 Vault Dweller's Survival Guide Map)