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Thicket Excavations

Thicket Excavations is a quarry located in the northwest of the Commonwealth in Fallout 4.


A Pre-War quarry that has flooded with water. Mirelurks reside in the bottom of it.


This marble quarry has gained a reputation as the source of the finest Mirelurk meat in the Commonwealth, thanks to the still water giving the meat a less brackish flavor.

Dive into the quarry pond, locating the three valves. Return to Sully, then activate the circuit breaker to switch on the pump and drain the quarry. Deal with any Mirelurks before accepting some Caps for your troubles.

After reaching level 12, return here after 24 hours to find the water drained and a bunch of Raiders rearing Mirelurks. Descend and search the Raider shacks for more items, including a steamer trunk to pillage.
Fallout 4 Vault Dweller's Survival Guide Map


The pre-War sign displaying the location's name is directly outside of the fence. It instructs visitors to check-in at the office, wearing safety equipment at all times, and includes a reminder that the area is not open to the public.

A fenced-in quarry area that has been flooded, it is found to have scattered pieces of cut stone around it. There are stairways leading up the north side of the quarry and a sloped ramp that extends into the water. The top-level on the east side includes an elevator as well as a camper in which Sully Mathis's terminal can be found which details his plans for restoring the quarry for use as a base. There are several campers spread out around the nearby area.

If the water is drained from the quarry during Pull the Plug, 24 hours have passed and one has reached level 12, then Sully will then (when the Sole Survivor next returns) be found to have brought in his gang of raiders, and these hostile raiders will be found spread out throughout the quarry. Sully Mathis will now be found to be much more powerful - minimum level 30 - and like the raiders will henceforth be implacably hostile regardless of any prior help he was given. Three mirelurk pens will also be found in the area.

There is a chemistry station part-way down towards the bottom of the excavation area. It is in a little shed on the south side of the quarry. At approximately the midsection of the quarry on the north side, a weapons workbench is accessible.


  • Taboo Tattoos issue #2 - In a metal trailer caravan (the one closest to the excavation area) on the south side of the excavation area and directly southwest of the water pump.
  • Sully's journal - Holotape in the east trailer inside of a terminal.

Related quests


  • The Thicket Excavations 'zone area' is one of a few places in Fallout 4 where an infinite supply of weapons, ammunition, medical supplies, food, water, and other junk may be obtained with no respawn delay. After Pull the Plug, the Sole Survivor can return repeatedly and crawl through the area, looting all of the containers and shelves. All of the materials will respawn infinitely with no delay, but the Sole Survivor must move far enough away for the respawn to occur (the railway tracks just south of Starlight Drive In is far enough). This quirk can and will eventually include infinite respawn of raiders and the mirelurks after the raider version of Sully Mathis (or his surrogate) is killed and his corpse has despawned (requires 20 in-game days without entering the zone area; this is possible to determine by the "[Cleared]" tag no longer being marked on the map for the location). There is an automated turret that will respawn with the raiders but may respawn in a slightly altered position with each visit (if destroyed). The obtainable materials in many locations change when Sully Mathis appears with the raiders and mirelurks after Pull the Plug (also, more items appear).
  • After the Pull the Plug quest, but before Sully Mathis appears with the raiders, anything left behind in the zone area can be retrieved later. When Sully Mathis and the raiders appear and the zone is marked as "[Cleared]" on the map, anything left behind in the zone area can be retrieved later until the zone area resets. When the zone resets ("[Cleared]" no longer marked on the map), from that point forward anything left behind will be lost as the zone will reset completely and immediately if the player character moves far enough away.
  • The Aquaboy/Aquagirl perk will allow the Sole Survivor to find some very minor loot underwater before completing the Pull the Plug quest. The content of the underwater containers will respawn after completing the quest.
  • The Thicket Excavations' raider camp respawns accordingly to the level of the Sole Survivor as well as the containers at the surface/bottom of the area, but Sully Mathis has a minimum level of 30. The trunk at the bottom does not respawn until Thicket Excavations has been drained.
  • While the quarry is flooded, the elevator will not function from the surface. Diving into the water while equipped with power armor may not be a good idea. If equipped with power armor, the Sole Survivor may not drown (depending on the Sole Survivor's position within the water), but they will immediately sink to the bottom of the quarry, unable to 'swim' back up. It is possible to walk around, potentially finding a route using stairways and platforms to make a return to the surface. It is also possible to reactivate the elevator by pressing the button right at the bottom. Wandering along the bottom of the quarry will be very time-consuming compared to swimming around and repairing the pipes without power armor. If the Sole Survivor does wind up at the bottom while in power armor, it may just be better to exit the power armor and then come back to the quarry when it has drained. So long as the fusion core is removed and a return trip to the zone area is made within a reasonable period of time, the abandoned power armor will still be there.
  • Attempting to place mines after completing Pull the Plug, but before the quarry has drained will not work, in the sense that the mines will all disappear when the zone area resets in its drained form.

Companion comments

When at this location companions make comments, which are activated near the water's edge both before and after the conclusion of the quest Pull the Plug.

Character Specific location Comment
Cait Before "Keep your gun handy. I doubt the only thing fillin' this quarry is a bunch of rocks."
After "Well, there's somethin' you don't get to see every day."
Codsworth Before "I wonder how the quarry flooded. Rainfall perhaps? Or maybe they dug right into a spring."
After "Oh my, that was really quite deep."
Curie Before "It would take a staggering number of gallons of water to fill this."
After "I am curious to see how the current biosphere interacts with this newly surfaced area."
Danse Before "Watch your step. It's impossible to get an accurate sounding without the proper equipment."
After "I wonder how long it will take before the quarry becomes inhabited again."
Deacon Before "Always wondered what's at the bottom of the quarry."
After "How about that. Scavengers will pick it clean in a year, but for right now what a sight."
Hancock Before "How long you think it took to fill this thing? Decades?"
After "Ours to scour."
MacCready Before "I wonder how many years of rainfall it took to fill this quarry."
After "Now all we do is wait a few decades for the rain to refill the quarry, come back and start the process all over again."
Nick Valentine Before "How far down you think it goes?"
After "Well, that ought to keep the Mirelurks away for a while."
Piper Before "Goodness. That could be hiding a lot of Mirelurks."
After "So much mud."
Preston Garvey Before "No telling how deep that is. Or what's living in it."
After "That did the trick. Drained the whole thing quicker than I would have thought."
X6-88 Before "Perfect spot for a mirelurk den."
After "With the water gone, we could take a closer look."


Thicket Excavations appears in Fallout 4 and Fallout Shelter Online.


  • PCPC Playstation 4Playstation 4 Xbox OneXbox One Upon arrival at Thicket Excavations, there seems to be a foglike low-res concrete-floor, hovering above most of the real surfaces, and it persists underwater. It is the high distance version of the model one should only see when the object is very far away. This manifests in that both the Sole Survivor and Sully Mathis wade knee-deep in concrete, Sully always hovers around the compressor/pump, before the Sole Survivor suddenly falls into the water or the access-way leading down into the excavation. The impact of this bug can be negated by restarting the game. [verified]
  • PCPC Playstation 4Playstation 4 Xbox OneXbox One If one swims underwater to enter the excavation site before draining it, they will fall down to the floor and be able to walk and shoot their gun underwater. In some cases, Dogmeat may also teleport down to the player character and swim in place as he tries to follow them.[verified]
  • PCPC Xbox OneXbox One Occasionally, the caged mirelurks will spawn outside of their cages. Caged mirelurks only turn hostile when attacked, or when the Sole Survivor (or a companion) enters their cage, so the mirelurks will roam around without turning hostile. [verified]
  • PCPC Playstation 4Playstation 4 Xbox OneXbox One Similar to one of the USS Constitution bugs, companions tend to repeat their location-specific comments over and over as long as they are in the quarry's vicinity. [verified]