Greely's Hideout is a members-only land den that was released January 22, 2015 in the Diamond Shop. It was rereleased on June 22, 2017.
The overall setting of the den is a large, phantom/Greely-themed volcano comparable to parts of The Search For Greely and Greely's Inferno. Visiting jammers enter in the heart of it, on top of a glowing blue emblem carved with different symbols. Directly south of that is a large lava pool, with bridges crossing over to a Greely cave, similar to the Greely's Passage item, with lava flowing from its mouth. There are areas with phantom pipes, purple ladders, and slides. At the very top, there seems to be a view of a Phantom Factory in the distance. To the top left of this area, which can only be accessed by the rocky cliff on the top left of the den, is an area with a view of what seems to be Jamaa Township.
- This is the second den to be completely based off an Alpha, the first being Cosmo's Den and the third being Peck's Den. After this, Liza's Garden was released, making it the fourth alpha den.
- It is one of the larger dens, and its size is comparable to the Crystal Palace and Sky Kingdom dens.
- When an animal gets close to lava in this den, their overall color gets a red tint, similar to the one from the Wolves Only Party. The other two dens to have this similar effect are the Snow Fort and Gingerbread House.
- Some Jammers believe that the Phantom Factory visible in the distance at the top of the den could be a hint to the next Adventure.
- In the AJHQ Greely's Hideout den on the Epic Dens list, jammers are not able to get the red tint on their animal from the lava.