Is Boulder a city?
By the US definition anywhere over 2500 inhabitants is a city. I reckon Boulder would pass out definition too though.
I once read an interesting article in a copy of Climbing magazine that ranked US cities using SCIENCE- in fact a bewildering variety of statistical categories. It was somewhere unexpected (to me at least) that came out on top, i.e. not Boulder or Salt Lake. It think it was in New Mexico, Arizona or possibly even Texas.
I get the impression that Las Vegas has year-round climbing possibilities. There are loads of US states with lots of climbing that non-Americans never think of too, but you have to take what they say with a pinch of salt as they think nothing of driving absurd distances of course.