The “Springfield” cat has been out of the bag for awhile. It’s in Kentucky.
I’m guessing Birmingham or Bloomfield Hills, seeing that Tim Allen owned a home in the former during the time he spent with the show. I’m not sure if he still has a home there…???
Someone had mentioned Charlotte earlier, but the only entry I saw was The Andy Griffith Show. That was, of course, in the fictional town of Mayberry, NC, which was based on the tiny Northern North Carolina mountain town of Mt. Airy.
Charlotte has had one show based in it. It was the short-lived (and rather awful) Nickelodeon kids show, My Brother and Me. In fact, ex-Charlotte Hornet Kendall Gill guest starred on one episode as “returning” to Charlotte. The father of the kids on the show was a sports writer for a ficticious Charlotte newspaper. 
Was McCloud really Forth Worth. I haven’t seen the show for over 20 years, but I distinctly remember him coming from Taos, NM.
Also, Hill Street Blues was not set in a city. It was never named in the show (as well as with Ed McBain’s 87th, which is also in a fictional city), but the location shots are from Chicago.
If I recall correctly (after fifteen or so years) McBain’s fictional city was called Isola. It’s a large thriving city halfway between Gotham and Metropolis.
Hill Street, on the other hand, was set in an unnamed city. Some of the exteriors and street names came from Chicago, but Daniel Travanti once refered to his character as being a New York City cop.
I haven’t seen Reno, Nevada mentioned yet. Anyone?
Ranchoth