This is the most comprehensive list of the community bands in the US. Although all are not listed and some on the list do not exist any more, it is the best place to start when looking for the community band in your neck of the woods. http://www.community-music.info/groups.html
Not really sure why, but it was good to see the one community band I participate with on the list, the Golden West Pops in Huntington Beach, CA. I'm principal sax player in the group, a big fish in a small pond. I'm also their webmaster, but I don't do floors or windows.