There are 10 Mikoyan Gurevich MIG 21 UM 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 1974 and 1988.
N57GS
1988 Mikoyan Gurevich MIG 21 UM
Hillsboro, OR
N221UM
1983 Mikoyan Gurevich MIG 21 UM
Reno, NV
N21EV
1974 Mikoyan Gurevich MIG 21 UM
Wilmington, DE
N21UT
1974 Mikoyan Gurevich MIG 21 UM
New York, NY
N1165
Mikoyan Gurevich MIG 21 UM
Mojave, CA
N20739
Mikoyan Gurevich MIG 21 UM
Wilmington, DE
N3751L
Mikoyan Gurevich MIG 21 UM
Hillsboro, OR
N7238T
Mikoyan Gurevich MIG 21 UM
Hillsboro, OR
N7803S
Mikoyan Gurevich MIG 21 UM
Sheridan, WY
N921UM
Mikoyan Gurevich MIG 21 UM
Fairhope, AL