Level 161, also known as the Cadaver House, is a highly undocumented and elusive level of the Backrooms. The Cadaver House has a reputation for being an extremely unnerving and isolated place that takes the form of a mansion. It possesses a seemingly endless amount of rooms and floors, stretching infinitely in all directions. All rooms are modeled after 1940s American suburban households and are made of representative material such as painted paper and glue. It is theorized that the Cadaver House is based on a collection of dioramas depicting American households during the mid-twentieth century.

Due to this construction, amenities located in the Cadaver House, such as bathtubs, sinks, toilets, refrigerators, showers, ovens, and stoves, are purely for decorative purposes and completely non-functional. All food and water in this level is fabricated or painted and ultimately inedible. For wanderers who find themselves in the Cadaver House, they will likely starve or die of dehydration within a matter of days if they do not have a pre-prepared supply of rations or cannot escape the level.

No bases, outposts, or communities exist on this level. Besides the Tinkerer and the occasional hapless wanderer, there is no sign of life in this level. Windows are present inside many rooms, but only look into other adjacent rooms. There is no perceivable sky, and it is unknown if the level possesses a day/night cycle. The overall temperature in the Cadaver House is rather chilly at approximately 60°F. (15°C) It never seems to fluctuate, even though there are no functional air conditioners or heaters present. However, for an unknown reason, a slight breeze can be found coming from underneath the closed doors to certain rooms. If one senses a breeze from a door, there is a very high chance that behind it will be one of the Cadaver House's key features and the reason for its namesake: a body.

In the Cadaver House, while there seems to be a lack of entities, several bodies can be found appearing intermittently in various positions inside a multitude of rooms. These bodies also appear to be representational — while they heavily resemble corpses, they are made of plastic and assumed to be life-size dolls. Each doll lies in a perfectly preserved state, similar to the body of a recently-deceased human. Every doll has been modified to represent various causes of death, with several being mutilated or otherwise injured. Painted blood is very frequent on the dolls' surface and on the surrounding area, implying violence. The apparent ages of the dolls vary. Some appear to be modelled after the elderly, while some take the appearance of young children. Each one can be presumed "dead" in one way or another. Almost always the cause of death of one particular doll is unique from any other dolls one may find in the Cadaver House. It is very rare to find multiple dolls that have been "killed" in the same way. Below are a few examples of documented bodies that have been found in the Cadaver House.

Body #1.

Body #2.

Body #3.

Body #4.

Body #5.

Body #6.

The only known picture of the Tinkerer.

There is currently only one living being that resides in the Cadaver House, named the "Tinkerer." It is, at the time of writing, unknown if the Tinkerer is an entity or human. He wears a plaid dress shirt and a red beanie. His apparent age is unknown, but he seems to be an adult. No efforts of communication or contact have succeeded, with the only photo of him being taken while he was unaware. The Tinkerer can be found randomly in rooms where there are corpse dolls. It is extremely rare to encounter him, and upon being seen, he immediately stops whatever he is currently doing and leaves the room without ever acknowledging the wanderer.

While the ultimate motives behind the Tinkerer's actions remain unknown, he exhibits observable patterns of behavior. The Tinkerer will move about the Cadaver House, searching for corpse dolls. Upon finding one, he will bend over next to the body and begin to examine it, performing a makeshift autopsy. The Tinkerer always carries with him a notebook and a pen, which he uses to take notes about the perceived cause of death, as well as any information about the doll when it was "alive", such as name, date of birth, and even hometown. The Tinkerer may also write down what he believes to be the motive behind the doll's death, usually proclaiming that they are either accidents or homicides. Upon completing the autopsy, reaching a conclusion, and finishing his notes, the Tinkerer will sign the note with his signature (which simply reads "the Tinkerer") and leave it by the body if it is on the ground or on an adjacent flat surface if the body is elevated. Approximately twenty notes have been recovered by wanderers so far. Included is an example of some of the Tinkerer's notes that wanderers have found.

There is only one entrance to the Cadaver House, and that is Level 5. The Cadaver House can be entered by finding and interacting with a dollhouse in one of the rooms in the main hall. As for exits, the only known way to exit the Cadaver House it to find a dark laundry room and enter one of the washing machines. Doing so may lead to Level 41. Not all washing machines will function this way, so wanderers will need to search for multiple in order to escape. If one finds themselves in the Cadaver House, attempt to escape immediately.