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.
Most of Yellowstone's landscape was created by volcanic eruptions more than 60,000 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 200 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 350 miles (560 kilometers) of roads and over 1,200 miles (1,900 kilometers) of
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 76 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
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.
More than 275 species of birds and nearly 50 kinds of other 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
Elk are the most common of the large animals in the park. Approximately 31,000 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 2,400 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, and cougars.
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.
More than 1,200 miles (1,900 kilometers) of trails provide a wide choice of hiking routes
through Yellowstone. Park naturalists offer guided hikes and evening campfire programs. TW
Services, Inc., has a program of 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 located 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
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.
Information may be obtained by writing Superintendent, P.O. Box 168, Yellowstone National
Park, WY 82190.
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.
One Indian tribe, the Sheepeaters, is known to have lived in the area of the present-day
park. Other tribes, 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 1916, when 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. The blaze burned large areas of forests and meadows, which have since
begun their natural cycle of regeneration.