Grunkle Stan has been living there a long time. It used to be his house but he turned it into a museum at some point. A young version of Stan is seen living in the Mystery Shack in "The Time Traveler's Pig," and Blendin Blandin revealed that 15 years ago a store sold costumes either at or next to the Mystery Shack.
The Mystery Shack has no less than four exits. The main entrance, the porch entrance, and another small door which directly to the floor room. and the gift shop door. There's also a cellar door under the gift shop window. One side of the sloping roof has the Mystery Shack name, and the other has a small platform with a cooler that Wendy often hangs out on. The roof with the "GIFT" sign also has a weather vane that has the letter W, H, A, T, instead of the usual N, W, E, S.
There are at least three floors that we know of.
The first floor has two levels, one where most of the rooms are located and a slightly lower level for the floor room.
- Gift Shop - Get all your Mystery Shack merchandise here! Normally where Wendy works behind the counter. This room as five exits. One is connected to the gift shop entrance of the Shack. The second is a curtained doorway to the floor room/exhibit/museum. A third door leads to the living room ("Employees Only"). The fourth is a ladder that goes up to the roof. And the last is a mysterious entrance through the vending machine.
- Living room - Where the Pines often watch TV. Notable features include: a table; a large yellow chair; and a dinosaur skull. One side leads to the gift shop, the other side has a doorway to the staircase entryway.
- Staircase entryway - Besides the staircase that leads upstairs, there are four doors in this small room: an exit to the back porch to its left, a door to the hallway past it, an entrance to the living room o it's right, and a doorway to the kitchen directly infront of it. The room itself has a stuffed "dodo" perched on a table and a ball hanging from a net.
- Kitchen - Features: kitchen table; a wide window; refrigerator with a stuffed wolf head sitting on it; a very old fashioned stove whose smoke pipe can be seen going through the roof from the outside. Also, although it looks physically impossible from the outside, it is directly infront of the staircase.
- Hallway - The hallway that connects the floor room to the staircase entryway. A bathroom is also found here as well as the door to the storage room.
- Bathroom - The bathroom has a small window, a bathtub, toilet, sink, cabinet, and a single light bulb. The tub is propped up by a stack of bricks on one side to keep level.
- Storage room - Originally wallpapered over after Stan put the wax figures in it. There's a window where Wax Abraham Lincoln stood under and then melted under the sunlight.
- Parlor - It has window and a fireplace. The location of Wax Stan's memorial, and where he was made by Mabel.
- Floor room - The exhibition is located here, showcasing weird oddities including: The Sascrotch, pterosaur, and jackalopes. Mostly multipurpose, it's also been converted to a dance floor and a hall of mirrors. There is also a bell rope that goes through the ceiling into the attic. This room has at least two exists, one small door leading directly outside and another above a short set of stairs that leads to the hallway.
- Attic Floor - a spacious room where the staircase leads to. It has a large stained glass window, designed with the eye of providence, and plush red window seat. The window looks out the back porch.
- Mabel and Dipper's Bedroom - Features: a triangular window that faces the same direction as the main entrance; multiple old arcade games; the bell rope that comes through the floor from the floor room; an alcove that has a fortune telling machine as well a coffin used as a TV table; and above that another small area with a second window (this one stained glass). There are two closets, one next to the exit (which didn't appear until Little Dipper) and one in the aclove, where the Dipper Clones shut "Dipper Classic" in.
- Only thing known is there's a hidden entrance that leads downstairs from the gift shop.
- Stan's Office - where the copier is located.
- Stan's bedroom
- Since "Headhunters," the "S" in "Shack" hangs off.
- Soos is the 'Employee of the Month' as shown in Double Dipper.
- The Mystery Shack's address is 618. June 18 is Alex Hirsch's birthday
- Stan appears to be harboring a sinister secret in the building that Gideon seems to be aware of, which is set to be revealed in a later episode.
- In the last scene of the first episode, Stan goes through the wrong entrance to get directly into the Gift Shop.
- Although there's a chimney stack going through Dipper's side of the room, logically there's no chimney on the right side of the roof, near the front of the Mystery Shack.
- Nearly every episode has the same error concerning the staircase entry, in that several reoccurring backgrounds have the stairs flat against the wall without any space for the door that's past it.
- In the past episodes, you can see a dodo bird near the front door albeit, in Summerween, the bird is replaced by a Jackalope.
Characters: Dipper Pines | Mabel Pines | Grunkle Stan | Soos | Wendy Corduroy | Waddles | Sheriff Blubs and Deputy Durland | Manly Dan | Old Man McGucket | Li'l Gideon | Robbie | Pacifica Northwest | Blendin Blandin | Bud Gleeful | Lazy Susan | Paper Jam Dipper | Rumble McSkirmish | Summerween Trickster | Toby Determined | Tyrone | Cute Biker | Dipper Clones | Tambry | Candy Chiu | Grenda | Thompson | Nate | Lee | Gnomes | 90's Teenagers | Pa and Ma | Manotaurs | Gobblewonker | Wax figures | Multi-Bear | Quentin Trembley | Deuce | Cheekums | Mermando
Episodes: Tourist Trapped | The Legend of the Gobblewonker | Headhunters | The Hand That Rocks the Mabel | The Inconveniencing | Dipper vs. Manliness | Double Dipper | Irrational Treasure | The Time Traveler's Pig | Fight Fighters | Little Dipper | Summerween | Boss Mabel | Bottomless Pit! | The Deep End | Carpet Diem | Boyz Crazy