The Crooked Lair

"You can't find the Crooked Man, no one can. There's no address, no place... He lives in the bends and forks of tree roots... behind the sun.. in the... shadows. The door to his house, it bounces around, never in one spot. You'll never find it. Even Crane had to use the Magic Mirror."

- The Jersey Devil to Bigby on the Crooked Lair

The Crooked Lair is the headquarters for the Crooked Man and his criminal enterprise. Located inside a desanctified church, the only way to enter it is through a magic door that constantly moves around Fabletown. The entrance is manned by Tiny Tim.

Episode 4: In Sheep's Clothing
Bigby gets his first information about the Crooked Lair from the Jersey Devil, after he and the Woodsman defeat him in a fight at the Lucky Pawn. Jersey says that the entrance to the lair magically moves around to different doors in the city, and never remains in one place for long. He advises that Bigby use the Magic Mirror to locate it, as that was the method Crane used. Bigby does so upon returning to the Business Office and repairing the Mirror, confirming Jersey's claims. The Mirror shows the door being under the Gothic Bridge in Central Park, and Bigby hurries there to catch it before it moves again.

Bigby arrives at the door and opens it, revealing a portal. He runs into it and is transported to the lair, where he is greeted by Tiny Tim. Tim informs him that the Crooked Man is waiting for him, and escorts him to the meeting room. Bigby either allows Tim to introduce him or walks in by himself, and is met by several enemies he has previously faced, including the Tweedles, Georgie and Vivian, and the Jersey Devil. Jersey moves to attack Bigby, but is stopped by the Crooked Man. He thanks Tim for his service and dismisses him, then addresses the sheriff, offering him a seat  and saying that they have much to discuss. Bigby can agree to do so, threaten him, or simply smoke, and the episode ends.

Episode 5: Cry Wolf
The Crooked Lair appears in the start of this episode, where it is revealed that the back of the lair has a portal to the door leading into it that reveals itself once shot. After Bigby races out of the lair to chase the Crooked Man, Mary and Georgie Porgie (leaving Dee, Dum (determinant) and the Jersey Devil inside of it), what happens to it is unknown, but it likely lost much meaning as the Crooked Man ends up either dead or imprisoned as a harmless crow by the episode's end.

Visitors
The Crooked Man is the owner, and likely the sole inhabitant, of the Crooked Lair. During the night of In Sheep's Clothing/Cry Wolf, he had a meeting (which judging by the conversation Bigby can hear if he eavesdrops on the door before entering it was revolving around a suitable action in response to Bigby's meddling). The other participants of it were Dee, Dum (if he was spared in A Crooked Mile), Georgie, Vivian and the Jersey Devil. As Bigby's discussion with the Crooked Man reached it's climax, Bloody Mary -- using the mirror in the room -- was able to arrive out of thin air.

Dee, Dum (if spared) and the Jersey Devil were last seen in-game in the lair.

Book of Fables Entry
"Occupying a desanctified church, this is just one of the many locations the Crooked Man's operation uses to run the Fabletown underworld. Its lounge atmosphere makes for a comfortable meeting place, unless you are an unwelcome guest. It is completely boarded up to the outside world, and the only way in is through one of the many portals, marked by a door with the Crooked Man's Catherine Wheel Icon, scattered throughout the city... and elsewhere"