Located on the edge of Grafton Lake, near Grafton and Morgantown in northern Appalachia, the dam was once one of the main sources of clean, hydroelectric power for the area. It was the primary source of power for the next-door Grafton Steel factory.
In the days leading up to the Great War, the dam became a hiding spot for Otis Pike and his nephew Freddy Wood, until Otis Pike died after being caught in one of Freddy's traps. After the bombs dropped, a series of earthquakes significantly lowered the dam's water levels, as recorded by former Director George N. Smith.
After the Great War, it became a focus of the Appalachian Brotherhood of Steel, becoming one of its frontier outposts. When Scribe Grant managed to get the generators repaired, it started providing clean power to Morgantown and Harpers Ferry again, helping them keep their trading routes open. However, its time came to an end with the rise of the scorchbeasts, which forced the Brotherhood to mothball the Dam and consolidate their forces to stand a chance of fighting them effectively. The super mutants seized the opportunity and took control of the dam and the outpost.
The area consists of the main building and a large storage building. The storage building has a power armor station and a tinker's workbench inside, along with a cooking station just outside the entrance. Super mutants and mutant hounds under the command of Harrison Malone occupy the dam.
The exterior of the main building in the dam is locked down with level 3 locks and a level 3 terminal on each door. Without the appropriate lockpicking skills, the only way to gain entrance is by dropping into a damaged drainage pipe on the east side of the facility. Once inside, collecting the Grafton Dam keys from a corpse on the first floor will allow one to exit the doors of the facility.
The drainage pipe leads into a slightly flooded basement area with another pipe that can be opened that leads to some mirelurk eggs and two toolboxes. There is also a catwalk that leads to the first floor of the facility that is guarded by a super mutant. There will be another super mutant in the building's interior on the second floor that may also fire at the player character. Following the catwalks around the first floor leads to some toy cars and toy trucks leading up to a bathroom scale that activated two springboard traps on either side of the door. Past this is a weapons workbench.
The upper level of the catwalks wraps around a room with three cymbal clapping monkeys, with two vertical blocks saying "hi" at the entrance to the room. The only way out from here is the upper level door. If one drops off the broken area of the upper level catwalk at the south end of the building, they will find the Grognak & the Ruby Ruins holotape in a large metal pipe.
- Battle of Huntersville speech - Holotape, lying on a shelf to the right upon entering the metal storage building.
- George Smith's memo - Holotape, underneath a cart on the upper level, in a room across from the one with the three monkey toys.
- Final orders for Grafton Dam - Note, underneath the Battle of Huntersville speech holotape.
- Esposito diary - page 12 - Note, on the bottom of a metal shelf to the left upon entering the storage building, above a sleeping bag and green footlocker.
- Freddy's Adventures - Three notes found during Cold Case.
- Diary of Otis Pike - Note, on Otis Pike's body during Cold Case.
- First day of command - Holotape, on the table to the right of Knight Moreno's terminal.
- Grognak & the Ruby Ruins - Holotape, below the collapsed catwalk on the upper level. The tape will be sitting inside of a large metal pipe.
- Grafton Dam keys - On a corpse on the first floor catwalk.
- Potential Vault-Tec bobblehead - In the blue catwalk office near the top floor, on the metal desk with a typewriter.
- Potential magazine - Located below the upper walkway and atop a small room within the main facility, in front of the outside of a metal pipe on the south side of the facility. It is the same pipe that holds the Grognak & the Ruby Ruins tape.
- Power armor chassis with T-series armor pieces - In the storage building at the power armor station.
- Stealth Boy - Outside, on the table to the right of Knight Moreno's terminal.
- Mini nuke - Located on a guard tower outside the dam's building closest to the entrance with the terminal, next to the yellow spotlights.
- Fusion core - In the fusion core generator at the east end of the first floor.
- Potential recipe - On a metal crate by the cooking station, with the pepper and sugar.
Grafton Dam appears only in Fallout 76.
Behind the scenes
Grafton Dam is likely based on Tygart Dam, located just south of Grafton in the real world.
- George Smith's memo
- Grafton Dam terminal entries
- Fort Defiance terminal entries
- Fallout 76 Vault Dweller's Survival Guide pp.314–315: "40. GRAFTON DAM
Route 92 to the north of Morgantown crosses the remains of Grafton Dam, on the border between The Forest and Toxic Valley. The irradiated waters of Grafton Lake are being held back by the intact dam wall. The actual dam structure is much more dilapidated and usually overrun by Super Mutants, though this was once a Brotherhood of Steel compound.
Getting into the dam building may be tricky, as the three exterior doors are all locked tight (3). Drop off the northeast exterior balcony onto the large outflow pipe with the skeletal corpse hanging from it. Sneak inside this way. Once inside, head to the ground-level gantry and up two more floors (watching for traps and foes); head to a series of blue metal maintenance huts on the gantry."
(Fallout 76 Vault Dweller's Survival Guide Atlas of Appalachia)