Yellowstone National Park, the oldest national park in the world, is famous for its many natural wonders. The park has more geysers and hot springs than any other area in the world. Yellowstone’s scenic attractions include deep canyons, thundering waterfalls, sparkling lakes, and vast evergreen forests broken by rolling meadows. Yellowstone is also one of the largest wildlife preserves in the United States. It has a greater concentration of large and small animals than any other area in the United States except Alaska. Bears, elk, and bison (American buffaloes) roam the park, and bald eagles, trumpeter swans, and white pelicans nest there.
Yellowstone lies in the northwest corner of Wyoming and spreads into Idaho and Montana. The park covers 2,200,000 acres (898,000 hectares). A series of high plateaus extends across the park, and mountains rise along Yellowstone’s northern, eastern, and western boundaries. The highest point, Eagle Peak, rises 11,358 feet (3,462 meters) in the Absaroka Range in the east.
Loading the player...Geysers
Most of Yellowstone’s landscape was created by volcanic eruptions about 600,000 years ago. A large mass of molten rock still lies beneath the surface of the park. This rock, called magma, furnishes the heat for the park’s geysers and hot springs. Yellowstone has more than 300 active geysers and thousands of hot springs.
The government established Yellowstone in 1872. It was named for the yellow rocks that lie along the part of the Yellowstone River that is north of the park. Over 21/2 million people visit Yellowstone yearly. Most of them drive through the park, but many explore large wilderness areas that can be reached only by foot or on horseback. The park has more than 450 miles (725 kilometers) of roads and over 1,000 miles (1,600 kilometers) of trails.
Touring Yellowstone
There are five entrances into Yellowstone National Park—two from Wyoming and three from Montana. Each entrance road connects with the Grand Loop, a 142-mile (229-kilometer) road that leads to major points of interest. The Grand Loop consists of the southern Lower Loop and the northern Upper Loop.
The Lower Loop.
The west entrance road joins the Lower Loop at Madison Junction. Southbound, the Lower Loop leads to several geyser basins. The Lower Geyser Basin includes the Fountain Paint Pots, a series of hot springs and bubbling pools of mud called mudpots or paintpots. The mudpots are formed by steam and other gases that rose from holes in the ground and changed the surrounding rock into clay. Minerals in the clay give the mud various colors. Great Fountain Geyser, also in the Lower Geyser Basin, erupts from the center of a large pool. The bursts of water from this geyser sometimes spout 200 feet (61 meters) above the pool.
Grand Prismatic Spring, in Midway Geyser Basin, is the largest hot spring in Yellowstone. Its pool, which has a deep blue center ringed with pale blue, measures 370 feet (113 meters) in diameter. Small water organisms called algae give the pool its color.
The Upper Geyser Basin has a large group of geysers. In most years, Old Faithful, the most famous geyser in the park, erupts about every 90 minutes. The actual intervals between eruptions vary from about 30 to 120 minutes. The geyser sends a stream of boiling water more than 100 feet (30 meters) into the air. Other geysers include Castle, Giantess, Grand, and Grotto. Morning Glory Pool, one of the basin’s most beautiful hot pools, resembles the morning-glory flower in color and shape.
Yellowstone Lake, which lies 7,733 feet (2,357 meters) above sea level, is the largest high-altitude lake in North America. It measures about 20 miles (32 kilometers) long and 14 miles (23 kilometers) wide. The lake has a shoreline of about 110 miles (180 kilometers). Geysers and hot springs occur along the shore at West Thumb. The Lower Loop follows the shoreline for 21 miles (34 kilometers), providing a view of the lake’s islands and the rugged mountains of the Absaroka Range.
The Grand Canyon of the Yellowstone cuts across the landscape for about 20 miles (32 kilometers). This canyon reaches a depth of about 1,200 feet (370 meters) in some places. The Yellowstone River runs through the canyon, creating two waterfalls. The Lower Falls plunges 308 feet (94 meters) and the Upper Falls 109 feet (33 meters) into the canyon. Views of the canyon are especially beautiful from Artist Point, Grandview Point, and Inspiration Point. See Yellowstone River.
The Upper Loop
leads north from Canyon with a climb through the mountains of the Washburn Range. Mount Washburn rises 10,243 feet (3,122 meters) on the east. Specimen Ridge, which can be seen from the road leading to the northeast entrance, has some of the park’s most famous petrified forests. The trees there were buried during volcanic eruptions about 50 million years ago by mudflows and streams carrying suspended earth and ash. Minerals from the mud and water seeped into the trees and turned them into stone.
At Mammoth Hot Springs, beautiful terraces are formed by gently flowing waters. The waters deposit a form of limestone called travertine, building large terraces one above the other. Algae and bacteria give some terraces various colors. Minerva Terrace and Opal Terrace are among the most beautiful in the area. The terraces change through the years as the waters deposit calcium carbonate, a mineral that builds up the formations. Some springs die, and the terraces become gray and lifeless. The Hoodoos are the remains of old hot-spring terraces broken up by landslides. 
Obsidian Cliff is a mountain of black glass that was formed by molten lava. Rootless vegetation called lichens now cover the glass in many places.
Norris Geyser Basin consists of hundreds of geysers, hot springs, and pools. It is the hottest and most active thermal area in Yellowstone. The temperature of the water in some of the springs reaches more than 400 °F (200 °C). Several geysers may erupt at the same time.
Plants and wildlife
Evergreen forests and mountain meadows cover most of Yellowstone. The most abundant tree is the lodgepole pine. Forests of Douglas-fir, Engelmann spruce, limber pine, and subalpine fir grow in some areas. During the summer, the mountain meadows display a variety of wildflowers, including the fringed gentian, Indian paintbrush, monkey flower, and mountain bluebell.
Hundreds of bird species and dozens of other kinds of animals live in the park. Trumpeter swans, blue herons, white pelicans, bald eagles, and gulls feed on fish in its lakes and rivers. These fish include cutthroat trout, grayling, mountain whitefish, and rainbow trout.
Elk are the most common of the large animals in the park. Approximately 30,000 elk live in the park in summer. About half of them stay there through the winter, but the rest wander south to warmer areas. Yellowstone has about 2,500 bison. These animals were widely hunted in the United States during the 1800’s. The protection provided by the park helped save them from being killed off completely. Other large animals in Yellowstone include black bears, grizzly bears, moose, mule deer, bighorn sheep, cougars, and wolves. 
In Yellowstone, the balance of nature is maintained through natural controls such as disease, weather, and competition for food (see Balance of nature). For example, if the park’s elk population becomes too large, many of the animals die during winters when food is scarce. In addition, park regulations protect the animal and plant life from human interference. The feeding of bears is prohibited not only because it is dangerous but because it disrupts their natural feeding habits.
Recreational activities
More than 1,000 miles (1,600 kilometers) of trails provide a wide choice of hiking routes through Yellowstone. Park naturalists offer guided hikes and evening campfire programs. A private company offers such programs as bus tours, horseback trips, stagecoach rides, and cookouts in summer.
Fishing in the park’s rivers and lakes is controlled by special regulations, and a permit is required. Hunting and the use of firearms are prohibited. Boats and canoes may be used on most of the lakes. Visitors must obtain a permit to use any type of boat or canoe.
Campgrounds are at Canyon, Madison Junction, Mammoth, Norris Junction, and other sites. A few major sites, including Canyon, Old Faithful, Mammoth, and Lake, have cottages, cabins, and hotels. Visitors who want to camp in the wilderness must have a permit.
During the winter, a heavy snow covers the park. All park roads, except the one connecting the north and northeast entrances, are closed. Snowmobiles may be used on the park’s roads, which are left unplowed but are groomed for snowmobile traffic. Cross-country skiers and snowshoers can travel over the park’s trails.
The website of the National Park Service at http://www.nps.gov provides more information.
History
Yellowstone’s landscape was shaped by the action of volcanoes and glaciers through millions of years. A large mass of magma, which lies about 1 to 2 miles (1.6 to 3.2 kilometers) below the surface of the park, has erupted more than 27 times during the past 2 million years.
A major volcanic eruption occurred in the Yellowstone area about 2 million years ago. About 600,000 years ago, another explosion of magma and gas created much of Yellowstone’s present-day geography. The eruption produced the Yellowstone Caldera, which is a huge crater about 47 miles (76 kilometers) long and 28 miles (45 kilometers) wide. Yellowstone Lake now occupies part of this crater.
Glaciers once covered much of the area. The last ones melted about 8,500 years ago and filled Yellowstone Lake. Outflow from the lake drained northward and helped shape the Grand Canyon of the Yellowstone.
An Eastern Shoshone group sometimes called the Sheepeaters are known to have lived in the area of the present-day park. Other Native American peoples, including the Bannock, the Crow, and the Blackfeet, crossed the area to hunt bison and elk.
The U.S. government obtained the Yellowstone region in 1803 as part of the Louisiana Purchase. John Colter, a member of the Lewis and Clark expedition, was the first white person to see Yellowstone. He traveled alone on foot through the area in 1807 (see Colter, John). Many trappers explored the area in the 1830’s and 1840’s. They returned with stories of spouting geysers, hot springs, and mudpots.
In 1870, General Henry D. Washburn, the surveyor general of the Montana Territory, led an expedition to check out the reports of the trappers. In 1871, a government expedition led by Ferdinand V. Hayden, a geologist, documented the unusual features of the area.
In 1872, Congress passed a bill to establish the park and preserve its natural resources. Civilian superintendents administered the park for the first few years, but they were unable to stop widespread hunting and trapping there. The Army took over control of the park in 1886 and began to protect the wildlife. A detachment of cavalry occupied the park until 1918, two years after Congress established the National Park Service. Today, the National Park Service manages Yellowstone. A superintendent, appointed by the director of the service and assisted by rangers, naturalists, and a maintenance staff, administers the park. Park headquarters are at Mammoth. 
In 1988, fires raged in Yellowstone. In keeping with park policy, the fires were allowed to burn naturally. Since that time, blazes have burned large areas of forests and meadows, allowing those areas to undergo natural cycles of regeneration. In June 2022, historic flooding swelled the Yellowstone River, severely damaging several park roads. Two of the park’s entrances were closed for weeks.
See also Colter, John; Old Faithful; Yellowstone River.
