Annual visitors: 4.3 million
Peak season: March to November
It's been called the “Disneyland of national parks” for a reason. While Yosemite covers more than 1,000 square miles, the vast majority of visitors flock to a single seven-mile-long-by-half-mile-wide spot: Yosemite Valley. In high season, cue the nightmare traffic jams, parking lot fiascos and 20-minute waits to use a restroom.
If you do find yourself amid the valley's soaring granite walls and waterfalls during busy times, seek a semblance of peace and quiet along the 11.5-mile Valley Loop Trail. You'll rub elbows with lots of folks on the trail's eastern half, but the farther west you walk (past Yosemite Falls along the base of El Capitan), the more people you'll lose.
To bypass the valley circus entirely, head for the less-crowded Tuolomne Meadows area, located high in the park's Sierra Nevada mountains. Along Tioga Road (usually open between late May and mid-November), you'll find superb picnic areas at Yosemite Creek and Tenaya Lake, plus several lightly trafficked hiking trails; the moderate Dog Lake trail is a nice choice.
Spend the night in the Eastern Sierra town of Lee Vining, where next-morning breakfast burritos at the Mono Market are a must.