Hello,
We are trying to compile a comlete list of MX tracks across the US over at http://www.monstermotocross.com/motocross-talk/. If you are a track owner/promoter or just someone who would like to list their favorite riding spot or track, please stop by and add to our database. When complete, this will be a valuable resource for any one looking for a place to ride. Thanks for your time.
Scott Reihart