Yellowstone  is perhaps the most accessible large national park in America. Nearly all of the famous sights are within a couple of hundred feet of the Grand Loop Road, a 142-mile figure-eight through the middle of the park. Whatever you do, don’t see Yellowstone at 45 miles per hour; that’s like seeing the Louvre from a passing train.
For all too many visitors, Yellowstone becomes a checklist of places to visit, geysers to watch, and animals to see. This tends to inspire an attitude that treats this great national treasure as a drive-through theme park, where the animals come out to perform and the geyser eruptions are predicted so everyone can be there on time.
Entrance to Yellowstone (307/344-7381, www.nps.gov/yell ) costs $25 per vehicle, or $12 for individuals entering by bicycle, foot, skis, or as a bus passenger. Motorcycles or snowmobiles are $20. The pass covers entrance to both Yellowstone and Grand Teton National Parks and is good for seven days.
If you’re planning to be here longer or to make additional visits, get an annual pass covering both parks for $50, or the Interagency Annual Pass—good for all national parks—for $80 per year. An Interagency Senior Pass for all national parks is available to anyone older than 62 for a one-time fee of $10, and people with disabilities can get a free Interagency Access Pass. Both of these latter passes also give you 50 percent reductions in most camping fees.
Upon entering the park, you’ll receive a Yellowstone map and a copy of Yellowstone Today, a quarterly newspaper that describes facilities and services and provides camping, fishing, and backcountry information. This is the best source for up-to-date park information. It’s also packed with enough warnings to scare off a platoon of Marines.
Examples include cautions against falling trees, bathing in thermal pools (hydrogen sulfide poisoning and meningitis), unpredictable wildlife, improper food storage, health problems from the altitude, narrow roads, theft, imitating wolf howls, leaving side mirrors attached when not pulling trailers, and scalding water. And, oh yes, “swim at your own risk.”
Pets are prohibited on trails, hydrothermal areas, or boardwalks anywhere in Yellowstone. Kennel facilities are not available in the park but can be found in Jackson  and Cody.
If you are planning a trip to Yellowstone, request a copy of the annual Yellowstone National Park Trip Planner booklet for an overview of sights, visitor centers, what to do, services, camping, and more. It’s also available on the park website, www.nps.gov/yell/planyourvisit . Call 307/344-2113 for a recorded park weather forecast.
The Park Service maintains visitor centers at Mammoth Hot Springs , Norris Geyser Basin , Old Faithful , Canyon Village , Fishing Bridge , and Grant Village . All of these sell maps and natural-history books covering the park and surrounding areas. In addition, you’ll find smaller information stations at Madison  and West Thumb  and a Park Service ranger at the West Yellowstone Visitor Center.
Open daily, the Albright Visitor Center (307/344-2263) at Mammoth is the only year-round visitor facility in Yellowstone.
New in 2010, the 26,000-square-foot Old Faithful Visitor Education Center (307/545-2750) is open daily mid-April-early November and mid-December-mid-March. Don’t miss this state-of-the-art building where tall windows frame eruptions of Old Faithful .
The modern Canyon Visitor Education Center (307/242-2550) is another must-see, with fascinating exhibits detailing park geology; it’s open daily early May-September.
Grant Visitor Center (307/242-2650, daily late May-Sept.) houses informative exhibits and a film on the role of fires in the park. Fishing Bridge Visitor Center (307/242-2450, daily late May-Sept.) contains decrepit exhibits of birds, animals, and geology.
Park Service personnel also staff the West Yellowstone Visitor Information Center (406/646-7701, daily late May-Oct.), just outside the park.
The speed limit on all park roads is a vigilantly enforced 45 mph (or less); exceed this and you’re likely to get a ticket! Be especially cautious on the south side of the park, where rangers seem to wait most evenings and the relatively straight road makes it easy to speed. During summer you’re not likely to approach the speed limit, because long lines of traffic form behind monstrous RVs or when wildlife is visible.
Gas stations are at Old Faithful , Canyon Village , Mammoth Hot Springs , Fishing Bridge , Grant Village , and Tower Junction , and repair services are available at all of these except Mammoth Hot Springs and Tower Junction. Additional service stations are in towns surrounding the park.
Most roads in Yellowstone close on the Monday after the first Sunday in November and usually open again by mid-May. Only the road between Mammoth and Cooke City is kept plowed all winter; other roads are groomed for snowmobiles and snowcoaches (snow conditions permitting) by mid-December. Plowing begins in early March, and the roads reopen in sections. The roads connecting Mammoth to West Yellowstone open first (typically mid-Apr.), while Dunraven Pass is plowed last. Spring storms may cause closures or restrictions on some park roads, so get current road conditions at entrance stations and visitor centers, or by calling 307/344-7381. (I’ve seen crowds of stranded travelers as passes were closed over a snowy Memorial Day weekend!)
Yellowstone’s roads have long been a source of irritation. Much of the roadbed was built at the turn of the 20th century, when horses and carriages were the primary means of travel. Increasing traffic and larger vehicles contributed to the deterioration of park roads, as did stretched-thin park maintenance budgets. Yellowstone is now nearing completion on a massive two-decade, $300 million reconstruction program, and each summer you’ll find a different section undergoing rebuilding. Be ready for delays of up to 30 minutes somewhere during your journey. Fortunately, all this work means that the roads are vastly better than they were in the 1980s. Contact the park’s 24-hour hotline at 307/344-2117 for the latest on the road situation and this year’s construction delays, or check the park newspaper. Road construction details can also be found online at www.nps.gov/yell/planyourvisit/roadclosures.htm .