Be sure to get a detailed topographical map before setting out on any overnight hike. Maps are available at many stores, visitor centers, and ranger stations throughout Yosemite National Park.

Permits & Fees

All overnight backpacking stays require a wilderness permit, available by phone, by mail, or in the park. Permits can be reserved 24 weeks before the permit office is open (Nov or Oct) and cost $5, plus $5 for each individual on the permit. Reservations are accepted, usually beginning in late winter. Call tel. 209/372-0740 or visit www.nps.gov/yose/planyourvisit/wpres.htm, and then print and fax the reservation form to tel. 209/372-0739 or mail it to Wilderness Permits, P.O. Box 545, Yosemite National Park, CA 95389.

If advance planning isn't your style, first-come, first-served permits are available up to 24 hours before your trip. Permit stations are located at the Yosemite Valley Wilderness Center, Wawona Information Station, Big Oak Flat Information Station, Hetch Hetchy Entrance Station, and Tuolumne Meadows Wilderness Center. (Many of these are open in summer only; Badger Pass is the lone winter-only permit station.) Permits for the popular trails, such as those leading to Half Dome, Little Yosemite Valley, and Cloud's Rest, go quickly. Call tel. 209/372-0200 for permit station locations and hours.

To get a permit, you must provide a name, address, telephone number, the number of people in your party, the method of travel (snowshoe, horse, foot), the number of horses or other pack animals if applicable, start and end dates, start and end trail heads, and principal destination. Include alternative dates and trail heads as well. Do not neglect getting a permit. You may hike for a week and never run into a ranger, but one is guaranteed to show up and ask to see your permit just as you are re-entering civilization.

Special Regulations & Warnings

Campfires are not allowed above 9,600 feet, and everything you take in must be packed out. Bears live in the high country, so stay alert: Backpackers are required to take bear-proof canisters for storing food. They can be rented for $5 a trip (and a $95 deposit on a credit card) at the Yosemite Valley Wilderness Center and several other park locations.

In the summer months, mosquitoes are public enemy number one, so bring plenty of repellent. Also pack sunscreen, since much of Yosemite's high country is on granite, above the tree line. Stay off high peaks during thunderstorms, and don't attempt a climb if it looks as though a storm is rolling in: The peaks are magnets for lightning.

The theme in the backcountry is "leave no trace," and that means packing out any garbage you take in, not bringing pets, and staying on designated trails and reusing existing designated campsites so you don't leave scars on the landscape. Fires are allowed only in established fire rings, and only dead and downed material may be used for firewood; fires are prohibited in some areas, but backpacking stoves are allowed throughout the parks. You must have a park permit for overnight stays in the backcountry. For more information on "leave no trace" ethics, see www.lnt.org.

Personal Safety Issues

It's best not to backpack alone, but if you must, be sure that you have told both park rangers and friends where you'll be and how long you'll be gone. Don't leave the parking lot without the following gear: a compass, topographical maps, a first-aid kit, bug repellent, toilet paper and a trowel of some sort, a flashlight, matches, a knife, a rope for hanging food supplies in a tree, and a bell or other noisemaker that hopefully will alert any bears in the neighborhood to your presence, as well as a tent, a stove, and a sleeping bag. At this altitude, sunscreen and sunglasses with UV protection are a wise addition. A recently developed bear repellent generically referred to as "pepper spray," available in most sporting-goods stores, has proven successful in countering bear attacks. You'll also need iodine pills or a good water filter because that seemingly clear stream is filled with parasites that are likely to cause intestinal disorders. If you don't have iodine or a filter, boil water for at least 5 minutes before you drink it.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.