Yosemite National Park, California

Climbers worldwide know about the granite rock formations in the Sierra Nevada mountains: Half Dome, El Capitan. And the pros know that Yosemite camping is either a feat of advanced planning, or a willingness to wing it for same-day reservations. 

There are 13 campgrounds inside the park with varying availability. The car campgrounds like Upper Pines require a reservation year-round (they sell out months in advance). To be fair, the reason why they sell out so quickly is because of the breathtaking beauty of the park. Between the massive sequoia trees, the mountains and the waterfalls, it's understandable.

Hogdon Meadow, Crane Flat, Wawona and Tuolumne Meadows campgrounds require reservations in the summer and fall months.  There are four first-come, first-served campgrounds north of the Yosemite Valley, while only Bridalveil Creek is reserved to early birds south of the valley. Camp 4, in the valley itself, is also first-come, first-served, but doesn't allow RVs or pull-behind trailers. (Oh, and for RVs, it's good to know that none of the campgrounds have hookups, but there are three dump stations.) If you're interested in trying for a first-come, first-serve site, get there early - they can fill up by 8:30 AM! The park service even has an availabilty hotline at 209-372-0266. 

Backcountry camping is available, but you have to get a wilderness permit to do so. Permits have the same basic set up as the campgrounds, some are available up to a year in advance for the planners, while the rest are first-come, first-served.