 
The White Desert is an area reachable by two routes: the Hat-and-scarf girl in the Block World and the FC world route that starts from the basement of the Mall. It is populated by a large number of notable creatures, including Monoko, Monoe, Dave Spector, Takofuusen and the Thing with The Quivering Jaw.
The desert's name is based off of its color, or rather, its lack thereof: Everything in the White Desert is entirely black and white, save for striking bits of red. Various limb-like objects protrude out of the surface, some moving when interacted with. This characteristic shows a similar design with the Eyeball World, in which animated hands and eyes are on the ground.
Stabbing the eye box has a 1/30 chance of teleporting you to a small area; getting back is done the same way. A passage that is a smiling tooth with two grasping hands brings one back to the Block World.
Speculation
The White Desert's monochrome design has been suggested in some theories as a representation of past events in Madotsuki's life. In these theories, Monoko and Monoe are typically seen as people Madotsuki knew at various times before shutting herself off from the world as they are monochrome as well. Monoko is said to be a girl who was injured/killed in a car crash, represented by her body having bones out of her body (among other injuries) appearing when the stoplight Effect is used. Monoe doesn't react in the same way, instead disappearing when talked to. This could mean that Monoe went away at some point, perhaps being contemptuous of Madotsuki (represented by the smirk she has in her full-screen event).
Maps
White Desert A Map
White Desert B Map
Map of the White Desert underground area
Map of the White Desert Path area
Monoe's Tunnel
Monoko's Tunnel
Inside the Eye Box
Connections
- FC World Dungeon
- White Desert Underground Lagoon
- White Desert A
- White Desert B (One Way) - Follow the path from the steps into the tunnel
- White Desert A
- White Desert Underground Lagoon
- Dense Woods B (The Road)
- White Desert A (Confined)
- The Place Where the thing with the quivering Jaw is
- White Desert A (Confined)
- The Block World
- White Desert B - Interact with Mafurako until she takes you to the black gate
- Monoko's Tunnel - Enter the long tunnel on the horizontal path
- Monoe's Tunnel - Kill the Dave Spector near the circular path with the Knife, then enter the tunnel from the west
- The White Desert Path - Kill the Dave Spector near the circular path, then enter the tunnel from the east
- The Eye Box - 1/30 chance of being transported when you stab the Eye Box with the knife
- White Desert B - Interact with Mafurako until she takes you to the black gate