@Packrat It is in a fictitious location called Derbyshire. It is implied that the focus is on the residents of this Derbyshire and their stewardship of Earth/humanity/monster-kind.
The setting and the physical location are discussed in several locations. From the main page, 'Our setting is modern Earth (present day), though Derbyshire is in a realm of its own. '
Theme overview is more OOC to explain it is dark super hero supernatural with some references to help correlate it to something known (League of Extraordinary Gentlemen, Hellboy, Miss Peregrine's Home for Peculiar Children). There is a theme file on that page for 'Derbyshire' that explains more about the fictitious location.
The Derbyshire page reiterates where the fictitious Derbyshire is: 'Derbyshire stands as bastion over earth, not quite inline with the physical world, resting somewhere in the beyond itself where it can guard against other intrusions as well.' and next paragraph, 'Physically in a realm between worlds, Derbyshire is composed of over 2,000 acres of space that includes ...'
I am sorry it does not directly say 'Derbyshire exists in a dimension that is not quite earth, but is accessible through ley lines and other means of crossing dimensions'. I wrote the theme more flavorful in context of how a character may understand, implying other 'realms' are other worlds or other dimensions. I did not write this using dimensional terminology, I will add this later today.
My second apology that it is a real location, this is my fault. I found Derby by searching unique surnames and ran with it instead of doing due diligence to find the real location. However, theme implies it existed on earth once before it was 'transplanted', I don't know the history of Derbyshire and Derby UK, but its typical with a lot of locations (noble estate, updated in 18th century to Palladian style architecture, nearby small 'village' where the common folks lived that served the estate/lord). It might further confuse things but Derbyshire Estates is also a location in Kentucky, US. Sorry our fictional location uses real world location names.