Similarly, KDIA is not in Denver (though its predecessor Stapleton was).
Actually it is.
The City and County of Denver annexed all that land in Adams County. They even have to have Denver cops, ambulances, and fire services out there. It's a completely separate group. Including their own dispatch, etc.
So it's truly "Denver" out there, halfway to Kansas.
It's relatively cushy duty, and you'll note a lot of the public safety folks out there are nearing retirement. The senior folks bid DIA to get out of the City and the insanity.
Another not-so-well-known outside of Denver fact:
Denver only hires people for these civil service jobs who live inside the City and County. (Unless this has changed while I wasn't looking.)
If you look carefully at a Metro area map, there are a couple of chunks of suburbia away from the main portion of the City that were annexed decades before DIA existed out near the Federal Penetentiary in Lakewood, CO. There are neighborhoods out there where every other house is owned by a Denver Policeman, Fireman, or EMT.
At least that's the way it was when I lived in Lakewood, many moons ago... and most job postings say "Must be a resident of the City and County or willing to relocate".
Never seen anyone try to take it to court as discriminatory that I recall. Mostly because besides the bennies, the City doesn't pay competitive wages compared to the surrounding suburban cities and counties. If you factor in the bennies, it's okay. Not great, but okay.