Digital radio in the US almost isn't a different service; it's kind of weird, digital is broadcast alongside the traditional analog, you tune the radio to the analog signal first and then digital subcarriers are available if you have a compatible receiver. Find me an American who isn't a broadcast engineer or ham that has any idea what the fuck I'm talking about; nobody uses that shit.

In my area (and the following paragraph will narrow that down to about 17,000 square miles), there are a lot of iHeartRadio affiliates like WDCG and WRCQ. You've got some locally owned conglomerates, like Capitol Radio that owns several prominent TV and radio stations chief among them is WRAL-TV and WRAL-FM. The biggest independent station, as in "one company, one transmitter" I can think of is WKRR transmitting a classic rock format on 92.3, home of the Two Idiots Named Chris show.

I'm not counting the public/college stations like WUNC, nor 88.1 Jesus FM WGOD.

The entire industry seems propped up by the drive time morning shows. The vast majority of Americans forgot about radio when they bought an mp3 player and now everybody uses Spotify. Or that one weird guy who's still got Pandora. Broadcast radio is mostly ads, so unless you're looking for news, weather or traffic you're better off with streaming services.