[CerberusBullet]

Well, let me see, I've lived in Las Vegas, NV; several parts of Florida; Pascagoula, MS; and Norfolk, VA(all of which are in the US) and I have to say, J-rock/J-pop are most popular in Las Vegas. There's more international connection there, as it's a bigger city. Florida is okay when it comes to J-rock, but people are more into manga and Japanese merchandise. Of all of them, Mississippi is the most out of it, but that's probably because everything is rebel pride and podunk, so I'm really not surprised.

Even so, in the places where J-rock and such are more popular, usually only Japan-o-files listen to J-rock(while we eat pocky and wear our Narutard pride headbands XD). You usually find all the Japanese stuff at Asian markets, bookstores and Hot-Topic.

Of course if you subscribe to Shonen Jump or Shojo Beat here in the US, you're pretty much in the loop anyways.