Let's be specific though: .gov is available for any government within these United States, whether it be federal, state, local municipality, territorial, or tribal government. In fact, all major cities I just spot-checked have .gov domains. I wonder how many are clinging to <city>.<state>.us? At least as a CNAME? ...none of those which I just spot-checked.
Plenty of exceptions abound, though: https://en.wikipedia.org/wiki/.gov#Use