Peak Fall Foliage: mid- to late-October
One of the busiest and oldest national parks is the mighty Yosemite, home to towering waterfalls and sequoias. Photographer Ansel Adams captured Yosemite's beauty in black and white, but you can visit in the fall and see it fully alive in color.
The northern California park spans more than 1,169 square miles with giant monoliths and mountains, rivers and lakes (3,200 of them!), and waterfalls dropping more than 2,400 feet.