Mass Pike Interchange before the Great War was an interchange between two elevated freeways, one heading north-south and one east-west, located near Lake Cochituate west of Boston. By 2287, Mass Pike Interchange has become inhabited by the Gunners, who have established an outpost on the freeway's ruins.
Sitting atop the western freeway, it consists of two roads: the freeway and the old highway. The old highway connects Mass Pike Tunnel west to the interchange and leads to the Nuka-World transit center at the west end of the highway. At the bottom and top of the freeway, the Sole Survivor will come across several Gunners. There are two elevators that can be used to reach the upper and lower sections of the freeway. The elevator to the lower freeway is located north of the interchange, while the second is located in the middle of the interchange, guarded by several Gunners. The uppermost section contains very few Gunners, while the lower section has several and an Assaultron, as well as a Gunner commander with power armor (T-45/T-51 and very rarely T-60). It also consists of numerous shacks containing loot. Near the power armor station, there is a shack that contains several items and a crate containing rare loot.
- Grognak the Barbarian issue #7 - In the commander's shack sitting on top of the toilet.
- Leveled power armor pieces - On the power armor station next to the Gunner commander's shack. Nearby Gunners will enter the power armor if alerted to the Sole Survivor's presence.
- A standing power armor - On the road northwest of the Mass Pike Interchange at a military checkpoint. Going west to Poseidon reservoir, one will see a couple of burned cars and a truck full of cigarette machines. Right beside the door.
- Two bottlecap mines - In the shed behind the weapons workbench.
- Long Road Ahead: MacCready will tell the Sole Survivor about his son Duncan, and how he has a disease that will ultimately kill him. He asks for help in tracking down the cure.
- In the Nuka-World add-on, a Gunner named Zachariah left his squad at the interchange because he was tired of being ordered around by Barnes and Winlock. He now resides in the Grandchester Mystery Mansion luring in wastelanders.
- In some cases the power armor pieces and frame will be standing inside the Gunner commander's shack in the same space as the bed. The power armor including pieces (armor pieces, fusion core) is inaccessible. To work around this, go to the power armor station and activate it: the power armor frame and all pieces will be placed on the power armor station.
The Mass Pike Interchange appears only in Fallout 4.
Behind the scenes
The Mass Pike Interchange (a.k.a. "turnpike") is a real location in Weston, Massachusetts, where Route 128 (Interstate 95) crosses under and connects with the turnpike. It is significantly closer to the Charles River in reality; the on-ramp and off-ramp for northbound traffic both cross over the river twice.
- Fallout 4 Vault Dweller's Survival Guide Collector's Edition p.317: "[3.21] MASS PIKE INTERCHANGE
This elevated highway interchange is now a well-defended and extremely defensible Gunner camp. There are two elevators to use; the one to the north has no nearby adversaries, whereas the one under the main central structure has a hut with Gunners waiting. The camp is behind the billboard signs, under the upper north-south freeway. However, by heading south and doubling back, you can climb and sneak above the camp. With careful maneuvering (and use of the curved elevated ramps), you can trek along the east-west freeway all the way to Mass Pike Tunnel West. A must for snipers."
(Fallout 4 Vault Dweller's Survival Guide Map)