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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 a surveillance facility used by the government before the Great War. The bunker was also a contingency plan and would serve as an outpost for government surveillance workers who were meant to continue their work well after the bombs fell. Not many workers made it to the bunker - a holotape recorded by an employee named Jeff Buzensky can be found on an employee's desk detailing the fall of the bunker and the death of his coworker Bill Stevens, who was a mere few steps away from the entrance after leaving to retrieve some personal effects from his vehicle. The shelter was not stocked with enough food due to budget cuts, and its inhabitants eventually died of starvation.[1]


On the outside of the facility, the abandoned shack has some highly irradiated water and nuclear waste barrels. The inside of the shack contains a locked trapdoor to the cellar next to Bill's skeleton and his suitcase, containing the key. The cellar leads to a large underground bunker with a large open shaft passing through the middle of the bunker. Up to three synths inhabit the bunker, one of which is a synth leader.

On the bottom floor of the bunker is a hackable terminal that can be used to reactivate the nearby elevator which leads back to the surface. However, this will also activate two hostile Protectrons, which the terminal fails to disable when prompted to do so.

Notable loot


  • The map marker changes from "Abandoned Shack" to "Federal Surveillance Center K-21B" after leaving the shack with the elevator.
  • There are only three actual "radios" in the facility, on a desk in the office on the center floor. The other radio objects in the facility are named "Surveillance Device" and emit only static.
  • If the player character remains friendly with the Institute after first entering it, the synths will be allied and will not attack the player character. The synths will speak with the same dialogue as the ones found in the Institute and throughout the Commonwealth.
  • The interior of this location does not reset.
  • Checking the database network after resetting the mainframe will show it as being online. However, all entries are deleted and text reading "For your safety, this database is now the property of the Brotherhood of Steel" can be seen.

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."


The abandoned shack appears only 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)