The Ashtray Maze is one of the locations in the Oldest House that Jesse Faden visits in Control. Its purpose is to prevent anyone without the Director's personal clearance from accessing Dimensional Research and the Hedron Chamber beyond.
The Ashtray Maze is a labyrinth of shifting corridors created by the Ashtray Object of Power under the binding of Director Trench in order to safeguard Dimensional Research and the Slide Projector. The nature of the maze causes anyone who happens upon it to become hopelessly lost or turned around, and permits only the one bound to the OoP (As well as those they designate) to pass through. Ahti is able to freely traverse the maze with no more difficulty than he would find in traversing the rest of the Oldest House, and in gifting his cassette player to Jesse, she is able to navigate the maze with a similar freedom. Though never conclusively stated, it is extremely unlikely that Trench granted natural passage through the maze to Ahti, due to his distrust of supernatural entities and his critical need to secure the areas beyond. It is known that there are civilians lost in the maze from prior to the Ashtray's retrieval by the FBC.
The Ashtray OoP itself is bound to Director Trench, though it is not made clear what effects his death has on this binding. It is possible that Jesse's initial attempt to traverse the maze returned her to the entrance because of Trench's death or because she had taken over as director. Hiss are encountered in the maze, but they seem to be focused on attacking Jesse rather than traversing the maze itself. Additionally, the maze in several instances prevents the Hiss from being able to reach Jesse — this indicates that the maze perhaps protects those with traversal privileges.
The first traversal by Jesse allows the player to fully experience the maze. Subsequent traversals teleport the player to near the end and back to the entrance.