If it is a Blackhawk (UH-60) then it is most likely from the Army National Guard located at the Cheyenne airport.
The Air Force at F.E. Warren fly the Hueys (UH-1) for base security and missile transport security. They use the call sign “Blade xx”
and can normally be heard on 271.9 am.
As for the Blackhawks transitioning the area I would listen to the CTAF (common traffic advisory frequencies) for Fort Collins/Loveland, Longmont, etc along with the Denver center freqs for the area.
I have forgotten the freqs for the area, but you can find them on airnav.com.
I moved from Severance 3 years ago.
Hope this helps out.
73, Rex