Riverside Manor was home to Frederick, Shannon and Olivia Rivers before and after the Great War. A secret facility in the basement was built before the war for Shannon's training as she prepared to portray the Mistress of Mystery in the upcoming Silver Shroud television series. To optimize her training Frederick bought, installed, and reprogrammed a custom RobCo computer mainframe called Cryptos that originated from a dropped Defense Intelligence Agency project.
After the war, the Rivers adopted many orphaned girls and later founded the Order of Mysteries to help the people of Appalachia by working in the shadows to eliminate threats, such as the raiders. The underground facility became the secret headquarters to the Order where the members trained and received their missions. The facility was also equipped with a fabricator that can create or repair the Order's equipment.
- 秘神會：委員會紀錄 - 在委員會會議終端機內的全像卡帶。
- 秘神會等級：新人/學徒/探子 - 從閨秘終端機取得。
- 秘神會：歡樂谷 - 同上。
- 秘神會：醫務室日記 - 在有終端密碼鎖住的醫務室內。
- 秘神會：製造日誌#194。- 在東南側的房間，製造終端機上。
- 秘神會：製造日誌#209。- 同上，武器工作台旁。
- 秘神會：製造日誌#212。- 同上，在工作台旁邊的終端機上。
- Random bobblehead - In a bureau on the second floor to the left of the main staircase and directly right of the main bedroom door.
- Fusion core - Sitting on a cart with a microscope in the basement near the weapons workbench.
The Pulowski Preservation shelters outside of the manor are secretly elevators into the basement. Once Into the Mystery is completed, simply activating the door while inside of the shelter will teleport the player character into the basement, but a worn veil or Veil of Secrets must be equipped to pass the laser grid. Using these shelters bypasses the Scorched inside and outside of the Manor but Mole rats spawn near the shelters.
Riverside Manor appears only in Fallout 76.