Alternate

Alternates are less a single Elsewhere and more a network of those scattered throughout the world, and connected to each other in a way that's less physical and more in terms of the general rule behind them. They are considered to be the Elsewheres that are the easiest to access by humans, as they are heavily connected to Earth, in fact being a special part of it more than a separate world.

Geography

Alternates are best described as something akin to a semi-cancerous overgrowth that grows over major population centers, being best described as a bit twisted version of the city in question coated in eternal life. It has been speculated for a long time among some initiates that Alternates are connected to human dreams, with some more knowledgeable speculating them to be a remnant of influence of the Ancient of Dreams.
There are certainly cases of initiates living in the city ending up dreaming of the local Alternate more often than they theoretically should. It's also believed to be a reason for people in the Alternate often feeling unspecified presence in their vicinity, especially at night, when a lot of people might be dreaming in the 'true' city.
The name itself is just a common description of those spaces - imagine 'Alternate X', with X being the name of the city. There is no hard threshold for when the Alternate begins to form. You can expect most of the world's capitals to have those, together with other major population centers. If you have a few million people living in one area, you can expect an Alternate to be there, although the exact size of it depends on the size of the city.
The exact status of the Alternate varies. Some of them are completely or partially overwhelmed by aberrants or undead. Others are home to a significant concentration of demihumans that changed them into their stronghold. Others - especially Alternates of capital cities - are under the direct control of the local national agencies for paranormal defenses and are used as hubs of the presence of the initiates of various types.

Statistics

Summary

Size: Varied
Danger Level: 1-2/5
Usefulness: 3/5
Accessibility: 5/5

Danger Details

Lesser Aberrant Presence: 0-2/5
Greater Aberrant Presence: 0-2/5
Gods Presence: 0-2/5
Demihuman Presence: 0-3/5
Undead Presence: 0-2/5
Cryptid Presence: 0/5
Other Threats: 0/5

Usefulness Details

Agriculture: 0/5
Mining: 0/5
Hunting: 0/5
Others: Habitable space for initiates/demis.