Many visitors to Yellowstone choose to camp so they can get the full outdoor experience, but it's important to plan ahead. If you don't reserve in advance during the busy summer months, plan to find your space before noon or you may have to go without. (Lands outside park boundaries offer much better availability to campers, though those too can fill by late afternoon.) A campsite costs about US$12-$17, US$35 for the Fishing Bridge RV Park. Those campgrounds accepting advance reservations are Bridge Bay, Canyon Village, Grant Village, Madison and Fishing Bridge (phone 307-344-7311, toll-free 866-439-7375). All others are first-come, first-served.

Noncampers have several choices, but it's essential to make arrangements early—at least six months in advance if you're visiting in the summer. Hotels, lodges and cabins are available (rooms and cabins come with or without private baths, so be sure to specify your preference). The cabins are quite comfortable and sometimes can be reserved just weeks in advance of a visit. Phone the park's central reservations office at 307-344-7311, toll-free 866-439-7375. Properties open at various times May-early June, and all close by the end of October. Old Faithful Snow Lodge and Mammoth Hot Springs Hotel reopen late December-March (access to the Snow Lodge is only by snowmobile or snow coach). Lodging in the park is comfortable but basic: None of the park's accommodations offer air-conditioning, TV or Internet hookups in the rooms. Telephones are in some hotel rooms, and all rooms are smoke-free.

The park contains several historic hotels, including Yellowstone's restored grande dame, Lake Yellowstone Hotel, and the charming and eccentric Old Faithful Inn.