Most centrist major cities

[Blue Rectangle]

Cincinnati?? Denver?? Im not sure,

Danver is quite liberal (socially especially) I would probably go with Indianapolis

Even if you take all the surounding counties (suburbs, which are comfortably Republican), the five-county area of Denver is still liberal overall.  It takes the entire rest of the state to balance Denver and give Republicans a moderate lead.

Here's some guesses for me, but I don't have much first-hand knowledge:
San Diego, CA
Sacramento, CA
Phoenix, AZ
Oklahoma City, OK
Reno, NV