While not diving related, my forums have a top-level category called "
Regional/State Forums". Under there, sub-categories like "
Great Lakes", "
Mid Atlantic", and "
Southwest", and under each of those, the actual forums where you post -
one for each state within that region, and including every state in the USA.
That way, the top level display looks clean, but people can dig down to their individual state if they so choose.
Start @ the
Regional/State forum and drill down to see what I mean:
http://forums.reservecops.com/forums.php