Key Takeaway
You can find Vault 81 by travelling to Chestnut Hillock Reservoir, to the west of Diamond City. Vault 81 is on the western side of the lake.
Paying a visit to Vault 81 is well worth your time in Fallout 4, with plenty of valuable items and characters to discover. Before you can do that though, you’ll need to know how to get there.
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What to Expect in Vault 81
If you haven’t stumbled across it by chance while exploring the Commonwealth, Vault 81 is a great location to seek out. As one of the last remaining fully functional vaults, Vault 81 is packed full of interesting NPCs. Players can interact and trade with these characters, as well as pick up a number of side quests that can have beneficial results.
One such quest leads to the player gaining a new companion. This is the scientific robot Curie, who has bags of personality and a highly enjoyable side quest of her own.
There are other benefits to discovering Vault 81 and exploring its content to the fullest. In particular, you can locate a new Bobblehead and the ability to obtain one of the best weapons in the game. This is the Overseer’s Guardian, a Legendary Combat Rifle that players can purchase from the Depot store inside Vault 81.
However, getting your hands on everything Vault 81 has to offer is only possible if you know how to find it.
Where Is Vault 81?
Vault 81 is located fairly centrally in the Commonwealth. However, its exact spot is somewhat tucked away and therefore easy to miss. Depending on the landmarks you’ve already unlocked, there are some handy fast travel points quite close by.
If you’re just starting out on your adventures, however, you’ll want to pull up your Pip-Boy map and locate the marker for Diamond City.
This should’ve been marked on your map early in the game, either as a result of speaking to Mama Murphy, Trashcan Carla, or somewhat randomly, by picking up the Wasteland Survival Guide magazine in Gorski Cabin, just south of Concord.
If you can find Diamond City, you’re not too far off from finding the location for Vault 81. On your Pip-Boy map, look for a small lake just off to the northwest of Diamond City. This is a location called Chestnut Hillock Reservoir. You’ll want to make your way there first, as Vault 81 is nearby, on the western side of the lake.
How to Get to Vault 81
Once you’re at Chestnut Hillock Reservoir, you’ll need to follow the pathway around the outside edge of the lake. Be careful here, as there are often swarms of bloodbugs, bloatflies, and stingwings lingering close by.
They’re especially present near the small cabin on the south shore of the lake, as there’s a decaying brahmin corpse named Bess just outside its front porch.
After dispatching the insects, make your way past the cabin and further up the path until you come to a slight fork in the road. There are some small tire walls and disused barriers at the edge of this fork.
Up ahead, the path will continue on into the built-up areas heading into The Fens. You want to ignore all this and turn around, heading back up the sloped path that leads toward a fenced-off area.
At the top of this small hill, you’ll see a fenced-off enclosure that’s home to some dilapidated shacks and burnt-out cars. Make your way toward the rock wall at the rear of this area and you’ll see an opening that leads into a cave. This will take you inside the entranceway to Vault 81.
Other Routes to Vault 81
You can also get to Vault 81 by following the train tracks all the way south from Oberland Station if you’ve discovered that settlement.
If you’ve discovered the Mass Pike Tunnel West, you can head directly north from here to locate Chestnut Hillock Reservoir. Or simply head to the northwest to reach the entrance to Vault 81. You’ll probably still need to drop down to the lake’s level to find it though.
Vault 81 Tips
You’ll need three fusion cores to get inside Vault 81. You can try and convince Overseer McNamara to let you in without them “as a fellow vault dweller,” but if your Charisma skill isn’t great then it’s easier to just hand over three cores for entry.
There are some useful magazines to collect inside Vault 81. Completing the Short Stories side quest will earn you a Grognak the Barbarian issue #5 comic, which you can pick up in the classroom. Do this before starting the Hole In The Wall quest though, or make sure you save Austin Engill when prompted to.
You can also pick up Taboo Tattoos issue #16 from inside Horatio’s barbershop in Vault 81.
Give blood to Dr. Forsythe when asked to do so. This may seem strange, given that he’s a character you just met, but doing so will secretly unlock the Hole In The Wall quest. You’ll want to do this quest in order to obtain the new companion Curie and be able to locate the Medicine Bobblehead.
Work through the Hole In The Wall Vault 81 quest before attempting to purchase the Overseer’s Guardian. Doing so will bag you a 10% discount at the Depot.
Keep an eye out for the Medicine Bobblehead in Curie’s office when exploring the lower reaches of the vault.
