A large domed cavern beneath Spruce Knob, it appears to be the location of a massive pre-War pumping facility and was further expanded by the settlers. The location was considered ideal for seeking shelter from scorchbeasts and the other dangers of Appalachia.
The elevator which leads into the hall is located roughly in the center of the cavern. To the north is Paige's office and a chemistry station. To the northeast is Aubrie's clinic. Directly east of the elevator is Jen's room, where Mochou can be found if she joins the Settlers. To the southeast is a barracks that will be occupied by the soldiers (Fields, Radcliff, Thompson, and Lucky) after they join. Down the stairs from the barracks are an armor and a tinker's workbench. The southern part of the cavern is the water pump station. The western computer area is occupied by Tutti Frutti and Penelope Hornwright after she joins Foundation.
- Aubrie Willem (if he survives Here to Stay)
- Captain Fields (after Duty Calls is completed)
- Lucky (after Duty Calls is completed)
- Mochou (after Invisible Ties is completed and she is allowed to join the Settlers)
- Penelope Hornwright (after Trade Secrets is completed)
- Recalibrated Liberator (after Invisible Ties is completed)
- Sergeant Radcliff (after Duty Calls is completed)
- Settler forager
- Sergeant Thompson (after Duty Calls is completed)
- Tutti Frutti
- The Old Guard, Vol 14: Ch 2 - Note, on a table in the southernmost cabin. Available after Duty Calls.
- Aubrie's notes - Note, on a table in Aubrie's clinic, east of where Paige is usually found. It cannot be taken and is only available after Here to Stay is completed and Aubrie returns to Foundation.
- Jen's journal, entry 1 - Holotape, on top of a table in Jen's room.
- Jen's goodbye - Holotape.
- Note from Jen - Two different notes.
- Paige's journal, entry 1 - Holotape, on a desk in a side room.
- Paige's journal, entry 2 - Holotape, on a counter near the aforementioned side room. Available after Trade Secrets.
- Paige's journal, entry 3 - Holotape, on a table against the window outside of the side room. Available after Invisible Ties.
- Paige's journal, entry 4 - Holotape, in the part of the room with a chemistry table, on a white computer console. Available after Duty Calls.
- Paige's journal, entry 5 - Holotape, in the same room, on top of a table surrounded by chairs. Available after Secrets Revealed.