Up on the border of Colorado and Wyoming is Soapstone Prairie , I think it is part of the National Park system, whereas the neighboring Red mountain park is Larimer county open space, and the northern part is Wyoming - Big Hole open space.
A herd of Bison are re-establishing there.
The Cheyenne rim trail was what attracted me up there, though there are a couple of other canyon trails I'd like to go explore more.