There are 3 Mikoyan Gurevich MIG-23UB aircraft on the U.S. registry that TailWiki has a page for. Every one is built from the public FAA record — year, serial, engine, home base, and registration history — and owners and pilots add photos, trips, and stories on top. The ones listed here were built between 1976 and 1981.
N23UB
1981 Mikoyan Gurevich MIG-23UB
Alto, TX
N51734
1976 Mikoyan Gurevich MIG-23UB
Saint Petersburg, FL
N5106E
Mikoyan Gurevich MIG-23UB
Saint Petersburg, FL