There was such a list on the Internet Bonsai CLub site, but it seems not yet to have made it to their new site.
It would probably be helpful to eMail Nic (their webmaster) to ask if it could be restored. Yes, I have an axe to grind, as I put considerable effort into my contributions to it. (
YOU try to describe Ron!
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Some state societies (Florida comes to mind) have directories within their area, as do some clubs.
Also, a Google on Bonsai and the State name may help. (Just tried it for Iowa
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(Added): I would second the reccomendations for New England Bonsai and Royal Bonsai, but would add Bonsai West to that list for Boston.