I didn't want to use names of towns with populations under 1000 people, but instead use geographic/park names...
I don't think that's possible. There's a lot of wilderness in that region, and most national parks are pretty big, so it would probably be impossible to find one for every territory. I suppose you could name territories after lakes, mountains, rivers, forests...but still, I think it would be easier to just forgo the no-towns-under-1,000-people rule.