The Plain of Sorrows

The Plain of Sorrows is Jack's home realm located in an alternate dimensional plain of existence. It made it's first appearance in the short story The Nightmare of Samuel Ward as the final place Samuel Ward visits in his nightmare.

History
Apart from the fact that it's Jack's home realm, almost nothing is known on the mysterious extradimensional plain known as The Plain of Sorrows. It's a place that no living human has entered and come out alive or sane, and has existed for as long as Jack has. The only known person to have ever entered and left was the San Francisco Private Detective Samuel Ward, who caught a brief glimpse of one of its ever changing forms. The Plain of Sorrows functions as a body drop, where the mutilated remains of some of Jack's victims are deposited, their restless spirits trapped within as the Gorekrows feast on their decomposing flesh.

Description
The true appearance of The Plain of Sorrows is unknown, as it's constantly warped and changed by Jack to fit his needs. In the short story The Nightmare of Samuel Ward, it takes on the appearance of a vast underground cavern filled with the corpses of Jack's victims which also make up part of its structure of stalactites and stalagmites. Also within this realm resides the mysterious creatures known as Gorekrows, functioning as the occasional harbingers of Jack's arrival and feed on the rotting flesh of the mutilated remains of Jack's victims.

Trivia

 * The Plain of Sorrows was originally called "The Dead Pits", and was intended to be a vast network of underground caverns where Jack would deposit the corpses of some of his victims.