whitfm said:
If I'm not mistaken, WSM in Nashville has been at least partially in a country music format since it signed on in 1925.
We will have to depend on our friends in Nashville to be the final word on this issue, but back in the 1960s I moved to a location that put Nashville on one of the two routes I could drive to go home and see famalies. WSM has been the home of the Grand Ol Opry for all those years, but I was surprised to learn as I traversed through Nashville in those years that weekday WSM was a very typical NBC middle-of-the-road station with good personable announcers that could have worked for any NBC or CBS station just about anywhere in the country. (No Southern twang!)
I don't think WSM is in the running for a long running format category.