Death Valley and MojaveLocation: Southern California
Known for: Breathtaking vistas, blasting 120-degree heat, mysterious moving rocks, and being the lowest point in the Western hemisphere.
Biggest crowds: Late fall through early spring (though rarely crowded even then)
Accessibility: You'll need a vehicle to get around the vast park; 4x4s are required on some back-country roads.
Why kids like it: The park has a Star Wars feel to it—which makes sense, since this was the location for the film's Tattoine (desert planet) scenes.
What hikers say: Don't venture out into this park without adequate clothing, sun protection, food, and water—even in the winter. The desert is very unforgiving.
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Palm Springs and Joshua Tree National ParkLocation: Southern California
Known for: World-class rock climbing, stunning desert scenery.
Biggest crowds: October through May
Accessibility: Much of the park can be seen from the roads that wind through its interior. Nature trails at Cap Rock, Oasis of Mara (adjacent to the visitor center), and Bajada are wheelchair accessible, as is Keys View overlook. There is an accessible campsite at Jumbo Rocks Campground.
Why kids like it: Giant piles of rocks are great places to play hide and seek—and encounter some strange critters.
What hikers say: Inspiring desert views lurk around almost every bend on the park's hiking trails.
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Sequoia and Kings CanyonLocation: Central California
Known for: Groves of giant sequoias and craggy Kings River Canyon.
Biggest crowds: Summer (especially weekends)
Accessibility: You can reach about 20 percent of park land via road, including major sights such as the General Sherman Tree and Grant Grove.
Why kids like it: They can run around the biggest trees they've ever seen.
What hikers say: Stunning and secluded back-country trails meander into the hills from the floor of Kings River Canyon.
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Yosemite National ParkLocation: Central California
Known for: Glacier-carved Yosemite Valley, ringed by soaring granite cliffs and shimmering waterfalls.
Biggest crowds: Summer
Accessibility: Dozens of famed features lie along paved roads. A free shuttle on the valley's flat floor links attractions and services.
Why kids like it: There are tons of ranger programs and campfires in summer, and a kids' ski school and ice skating in winter.
What hikers say: You can leave the crowds behind and head for the high country trails around Tuolumne Meadows and along Tioga Road.
Best for:Visit the Travel Talk forums for help on planning your trip