I don’t think so, the transmitter was under the power limit for amateur FM, and it didn’t overlap any local stations. That was my interpretation of the law as I read it before I built the station, doesn’t make it accurate or authoritative though.

A legal unlicensed FM transmitter could possibly cover a small area as described.

If it's line-of-sight on a frequency with no interference and stays at the legal limit of 250 microvolts per meter measured at 3 meters, and there's a good receiver with a good antenna, it's possible.