Looks like Yellowstone was a very busy place last year. I didn’t personally get there, but I did visit Arches, Zion, Bryce, and Grand Teton. I expect the economy played into the increased park attendance with people vacationing closer to home. Plus the Ken Burns documentary might have pushed a few people out the door that might not have otherwise gone. Check out the full details: Yellowstone National Park – Record Numbers Visited Yellowstone In 2009 (U.S. National Park Service)