Yellowstone National Park

At its heart Yellowstone is a volcano, though not the kind that makes a single tall cone. It is a caldera, a giant sunken bowl left behind by enormous eruptions long ago, and it is still very much alive underneath. That is why the park holds half the world's geysers and more than 10,000 hot springs, mud pots, and steam vents. Old Faithful is the most reliable big geyser on Earth, erupting roughly every 90 minutes, and Grand Prismatic Spring is the largest hot spring in the country, its rings of color made by tiny heat-loving bacteria living at the cooler edges. Rangers even post the next predicted eruption time so families can plan their afternoon around it.

Yellowstone is also one of the best places in the lower 48 states to see big wild animals living free. The Lamar Valley in the northeast is often called the Serengeti of North America for its herds of bison and elk and the wolves that hunt them, and the Hayden Valley in the center is just as rich. Bison graze right along the roads, elk bugle in the fall, and both grizzly and black bears roam the backcountry. Wolves were brought back to the park in 1995 after being gone for decades, and today people come from all over the world just to watch them at dawn.

Beyond the thermal areas and the wildlife, the landscape keeps changing as you drive. Near the north entrance, Mammoth Hot Springs builds terraces of white and tan travertine, a soft rock that hot water leaves behind as it cools. Farther in, the Grand Canyon of the Yellowstone cuts a thousand feet down through golden-yellow rock, with two big waterfalls thundering over the edge. And in the southeast, Yellowstone Lake sits at 7,732 feet above sea level, one of the largest high-altitude lakes on the continent, cold and deep and ringed by peaks.

• North Entrance at Gardiner, Montana, off US-89, is open to cars year-round and is the only road entrance you can reach by vehicle in winter. It leads to Mammoth Hot Springs and the Lamar Valley.
• West Entrance at West Yellowstone, Montana, off US-20, is seasonal and snow-dependent, and it is the busiest gateway in summer.
• South Entrance, off US-89/191/287, connects Yellowstone to Grand Teton National Park just to the south and is seasonal and snow-dependent.
• East Entrance, off US-14/16/20 from Cody, Wyoming, follows the scenic Cody Road through the Wapiti Valley and is seasonal and snow-dependent.
• Northeast Entrance at Cooke City, Montana, off US-212, connects to the dramatic Beartooth Highway and is seasonal and snow-dependent.
• Most travelers come from the west through West Yellowstone, from the south by way of Jackson and Grand Teton, or from the east through Cody, which sits about 53 miles from the East Entrance, roughly an hour and a half of scenic driving. In winter, plan to enter through Gardiner in the north, the only gateway open to cars.

• North Entrance (Gardiner, MT): The historic front door and the only winter-accessible road entrance, leading to Mammoth Hot Springs and the wildlife-rich Lamar Valley. This corner of the park opens the way to half the world's geysers, the world's largest petrified forest, and the largest high-altitude lake in North America, with Old Faithful erupting about every 90 minutes deeper inside.
• East Entrance (Cody, WY): Reached by the 52-mile Cody Road through the Wapiti Valley, a stretch Theodore Roosevelt once called the most scenic 52 miles in the United States. The east side of the park includes Sylvan Lake at 8,530 feet and the shore of Yellowstone Lake.

• Lamar Valley is the Serengeti of North America, the best wildlife viewing in the lower 48, where bison herds, elk, and wolves move across a wide green basin, especially at dawn and dusk.
• Grand Prismatic Spring is the largest hot spring in the United States, and its full rainbow of color is best seen from the short uphill overlook trail across the road from the main boardwalk.
• The Grand Canyon of the Yellowstone is a 1,000-foot-deep canyon of golden rock with two major waterfalls, seen from overlooks like Artist Point.
• Mammoth Hot Springs near the north entrance is a stack of active travertine terraces, white and tan rock built up by cooling mineral water, laced with boardwalks.
• Yellowstone Lake is a 136-square-mile lake at 7,732 feet, the largest in North America above 7,000 feet, cold and clear beneath the peaks.
• Fishing Bridge is a historic 1937 bridge over the Yellowstone River near the lake's outlet, a classic spot to pause.
• Mud Volcano and Dragon's Mouth Spring are churning, bubbling hydrothermal features on the east side, loud and steaming and easy to reach by boardwalk.
• Hayden Valley holds the best bison herds in the park and is prime wolf territory, a broad meadow along the Yellowstone River.

People have lived with this land for more than 10,000 years, and many tribes hold deep ties to it. The Crow, Eastern Shoshone, Blackfeet, Bannock, and others hunted, fished, gathered, and traveled through the region, and a band of Mountain Shoshone known as the Sheep Eaters, or Tukudika, made their home in the high country here year-round. To these nations the steaming ground was familiar and meaningful, a place woven into their lives and stories long before any map named it. Their connection to this landscape continues today.

Word of a place where the ground boiled and rivers of steam rose from the earth reached the wider country through trappers and early travelers, and for a while few believed the tales. Formal expeditions in 1870 and 1871 finally brought back detailed reports, and the paintings of Thomas Moran and the photographs of William Henry Jackson showed the rest of the nation that the wonders were real. Their images helped convince Congress to protect the area before it could be carved up or spoiled.

On March 1, 1872, President Ulysses S. Grant signed the act that created Yellowstone National Park, the first national park anywhere in the world. It was a brand-new idea, that a great landscape could be set aside and kept for everyone, and it became a model copied across the United States and around the globe. In the early years the park was fragile and poorly funded, and for decades the U.S. Army was sent in to guard it from poachers and vandals before the new National Park Service took over in 1916.

The park changed again over the following century. The Civilian Conservation Corps built roads, trails, and buildings during the 1930s, and the grand log lodges near Old Faithful and the lake became landmarks in their own right. In 1988 huge wildfires swept across much of Yellowstone, and the forest that grew back taught scientists how fire renews these lands. In 1995 wolves were returned to the park after being wiped out decades earlier, restoring a missing piece of the wild balance that visitors now travel far to witness.

• Yellowstone was the first national park in the world, created in 1872, and the idea spread from here to more than 100 countries.
• The park sits on top of a supervolcano, one of the largest active volcanic systems on Earth, and the heat from it feeds more than 10,000 hydrothermal features.
• About half of all the geysers on the entire planet are inside Yellowstone, more than in any other place in the world.
• The colorful rings around hot springs like Grand Prismatic are made by living things, tiny heat-loving bacteria called thermophiles that thrive in water far too hot for anything else.
• Yellowstone holds the world's largest petrified forest, ancient trees turned to stone, some still standing upright where they grew.
• Old Faithful is not the biggest geyser in the park, but it is the most predictable, which is how it earned its name from early visitors.
• The Grand Canyon of the Yellowstone is painted yellow by minerals in the rock changed by ancient hot water, and some people believe the park's very name comes from that golden stone.
• Wolves were completely gone from Yellowstone for about 70 years until they were brought back in 1995, and their return changed the whole ecosystem, even the paths of some rivers.

• An entrance fee applies (per vehicle, good for seven days), and interagency annual passes are accepted; check the park website for current rates.
• The North Entrance at Gardiner is open to cars year-round and is the only winter-accessible road entrance.
• The Grand Loop Road is a 142-mile figure-eight that connects the major attractions; give yourself time, as it is a big park.
• For wildlife, aim for dawn and dusk in the Lamar Valley to look for wolves and bison.
• Bear spray is required for backcountry travel, and it is a smart thing to carry anywhere you hike.
• The East Entrance is generally open late May through early November.
• Cody sits about 53 miles east of the park; plan around an hour and a half for the scenic Cody Road drive.
• The Fishing Bridge Visitor Center sits on the east shore of Yellowstone Lake.
• There are no vehicle size restrictions on the East Entrance road, which is helpful for larger RVs.

Yes. Yellowstone charges a per-vehicle entrance fee that is good for seven days, and interagency annual passes are accepted; check the National Park Service website for the current rate. The park is technically open all year, but only the North Entrance at Gardiner stays open to cars in winter. Most interior roads close to regular vehicles from about early November until late spring.

Most of Yellowstone's interior roads close to cars for the winter, generally from around early November into spring, once the snow piles up. During that season the park is reached by oversnow travel only, meaning guided snowcoach or snowmobile tours, except for the road between the North Entrance at Gardiner and the Northeast Entrance at Cooke City, which is plowed. If you want to drive the full loop yourself, plan a summer trip.

Yellowstone does not currently use a general timed-entry system, but that can change from year to year, so check the park website before you go. What matters most is lodging: rooms and campsites inside the park book up many months in advance, often close to a year ahead for summer, so reserve as early as you can. Towns just outside the gates offer more options if the park fills up.

Always stay on the boardwalks and marked trails in every thermal area. The water in the springs and geysers is often near or above boiling, and the crust of ground around them can be thin and hide scalding pools just below. People and pets have been badly burned stepping off the path. Keep a firm hold on children, leave pets in the car or at the trailhead, and never touch or wade into any thermal water.

Give animals plenty of room. Stay at least 25 yards, about the length of two school buses, from bison, elk, and most other animals, and stay at least 100 yards from bears and wolves. These are wild animals, and bison in particular injure more visitors than any other animal in the park when people crowd them for photos. Watch from your car or from a safe distance and never feed or approach wildlife.

Yellowstone is home to both grizzly and black bears, and bear spray is required for backcountry travel and strongly recommended anywhere you hike. Carry it where you can reach it fast, hike in groups, make noise so you do not surprise a bear, and store food properly. Keep the recommended distance of at least 100 yards from any bear you see and never get between a bear and its cubs.

Yellowstone is huge, and the Grand Loop Road runs 142 miles, so a single day only scratches the surface. Two to three full days let you see Old Faithful and the geyser basins, the Grand Canyon of the Yellowstone, Mammoth Hot Springs, and a valley or two for wildlife without rushing. Four or five days give you time to slow down, hike, and watch for wolves at dawn.

Summer, roughly June through September, brings open roads, warm days, and full access, though it is also the busiest and most crowded time. Late spring and early fall are quieter, with active wildlife and cooler weather. Winter is a world of its own, snowy and silent with steaming geysers, but you can only reach the interior by snowcoach or snowmobile, so plan accordingly.

For most first-time visitors the must-sees are Old Faithful and the geyser basins around it, Grand Prismatic Spring seen from the overlook trail, the Grand Canyon of the Yellowstone with its waterfalls, and Mammoth Hot Springs. For wildlife, spend an early morning in the Lamar Valley or the Hayden Valley watching for bison, elk, and wolves. Together these show off the park's two great gifts, its thermal wonders and its wild animals.

Pets are allowed in Yellowstone but only in limited areas: developed spots, roadsides, parking lots, and campgrounds, always on a leash no longer than six feet. They are not allowed on trails, boardwalks, in the backcountry, or in thermal areas, which are the very places most people want to explore. Never leave a pet in a hot car, and check the park website for the current pet rules before you go.