While reserving a spot inside a national park isn’t the only way to camp near popular nature sites, it is well worth the foresight if you can book a few nights ahead of time.
Every park has its own schedule of openings, reservation requirements and campsite availability, so the best advice is to closely track a few parks for announcements. While some national parks save a portion of their campsite reservations to be released a week before booking, most park reservations open six months in advance.
Most National Parks reserve a few spots per campground as a first-come, first-serve option. They can be impossible to predict, so do not rely on their availability if you are set on camping inside the park. Note that reservations often become available at 8 a.m. in the time zone of that park. Permits for popular hikes and activities also become available at this time at recreation.gov.
Timed entry reservations will still be required at a handful of popular parks during the peak summer months: Yosemite, Arches, Zion, Glacier, Rocky Mountain, and Haleakalā National Parks will all require some reservation to enter. To the National Park Service’s credit, these required dates cluster around the most popular weeks and holidays, and there are usually exceptions, like entering a park before 5 a.m., that still allow for some flexibility if you can’t score a reservation in time.