Where: Washington

Why: The “American Alps” boast nearly 400 miles of hiking, from the forested valley bottoms to leg-burning, switchbacking climbs up steep passes and ridges to where more than 300 glaciers cling to the frosty spires, peaks and horns of the Cascades. More than 9,000 feet of vertical relief lend the mostly wilderness park a huge variety of ecosystems—from temperate rain forest to alpine—and, in turn, trails to suit almost every taste. More Info

Runner-up: Bryce Canyon National Park, Utah

For warmer hiking hues, try Bryce Canyon National Park at dawn or dusk, when the sun illuminates its outlandish hoodoos with wild oranges, red, pinks and yellows. More Info