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 Pike'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 a 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.
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 to 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.
- 亨特斯維爾之役演講 - 發電站外頭的帳篷下，架子上。
- 格拉夫頓水壩的最後命令 - 同上。
- 艾斯波西托日記：第12頁 -同上區域，金屬架上。
- 喬治·史密斯的備忘錄 - 樓上靠近外面出口有著三隻猴子玩具的房間出來通道的手推車底下，不好取得需離它遠一點。
- 弗雷迪的冒險#1/2/3 - 懸案任務期間於發電站內找到，有三份。
- 奧提斯·派克的日記 - 懸案期間於發電站內找到，在奧提斯·派克的屍體上。
- 接掌首日 - 莫雷諾騎士的終端機旁桌上。
- 格拉夫頓水壩鑰匙 - 一樓檢修通道的屍體上。
- Random magazine - Located below the upper walkway within the main facility, in a metal pipe on the south side of the facility.
- Random Vault-Tec bobblehead - On the desk at the end of the catwalk leading to the last floor.
- Power armor chassis with T-series armor pieces - In the storage building at the power armor station.
- Random recipe - On a metal crate by the cooking station, with the pepper and sugar.
- Stealth Boy - On the table to the right of Knight Moreno's terminal.
- Mini nuke - Located on a guard tower outside the dam 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.
- 《古古那與紅寶石遺跡》 - 發電廠內，從西南邊的辦公室跳下來，金屬管子裡。
Grafton Dam appears only in Fallout 76.