Yellowstone National Park

• 1. Introduction

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  On the 1st of March 1872, President Ulysses S. Grant signed a law that created Yellowstone National Park in the northwest corner of Wyoming. Small slices of the park reach into Montana and Idaho, and the whole area covers 3468.4 square miles. Congress described the land as "dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people." It was the first national park in the United States, and it is widely understood to be the first anywhere in the world.

  The phrase "pleasuring ground" hides a much larger story. People had lived around these lakes and canyons long before any senator heard of them. Who were they, and what did they leave behind? Why did early tales from the region sound like tall stories? How did the new park survive poachers and hostile local interests? What lies beneath the ground to power so many geysers? And what happens to a protected wilderness when its predators vanish and return, or when flames and floods arrive? The chapters ahead follow those questions.

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• 2. First Peoples

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  In the 1950s, workers building a post office in Gardiner, Montana, turned up an obsidian point of Clovis origin. It was about 11,000 years old. Native Americans had been in the Yellowstone region for at least that long, and the archaeological record shows continuous use from the earliest human presence in the Americas until the park's founding.

  The Cody complex made the earliest consistent visits, around 7300 BC. Evidence from the Mummy Cave site suggests these people followed migrating bison herds into Yellowstone. They also mined obsidian from Obsidian Cliff. Excavations show that Cody people spent summers on the eastern side of Yellowstone Lake, where they fished, boated, and hunted bear, deer, and bison.

  Obsidian Cliff drew its heaviest use in the Late Prehistoric period, from 1000 BC to 1000 AD. Between roughly 200 BC and 400 AD, thousands of pounds of its stone traveled thousands of miles to Ohio along the Missouri, Mississippi, and Ohio rivers. The Hopewell Culture used it for ceremonial goods. Hopewell graves also held copper shaped like the horns of Rocky Mountain bighorn sheep. That detail hints that Hopewell travelers may have come to Yellowstone themselves.

  Around 500-1000 AD, the Shoshone summered at the southern end of Yellowstone Lake. The Crow, Nez Perce, Blackfoot, and Salish probably visited regularly as well, though archaeological findings are lacking for them. Oral traditions among the Shoshone, Blackfoot, and Salish recall women gathering cinnabar and other resources at Obsidian Cliff and offering prayers there.

  Low-intensity fires were the land management tool of the pre-Columbian peoples in Yellowstone's forests. They knew that fire brought up green grass, and that green grass drew bison.

  The region's names survive in several Native languages. In Assiniboine it is pashaka, meaning "white mountain country." The Crow called it aw' pawishe, "land of steam," and the Nez Perce said memut neespah, "boiling earth." The English name comes from the Hidatsa word miʔcíiriaashish for the Yellowstone River. David Thompson's expedition translated it as "Yellow Stone" in 1797.

  In the early 1700s, the Shoshone became the first Rocky Mountain tribe to obtain horses. The Tukudeka, or Sheepeaters, the Shoshone band living inside Yellowstone, did not use them and tracked bighorn sheep on foot. From the 1840s, the Bannock rode from their home near Henrys Lake through Mammoth Hot Springs on the way to buffalo hunts in the Bighorn Mountains. Those hunts took place in Crow country. Park rangers now call the route the Great Bannock Trail. It let the Bannock spend time with the Crow, their allies against the Blackfoot Confederacy. Soldiers would soon have reason to care about that trail.

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• 3. Rumors and Expeditions

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  A letter written to James Wilkinson in September 1805 holds the first written report of anything unusual at Yellowstone, and it repeated only second-hand accounts. In the winter of 1807-1808, John Colter, a former member of the Lewis and Clark Expedition, passed through the northeast corner of what became the park, near Tower Fall. He called a steaming site outside today's park boundary "hell" because of its sulphur smell. Washington Irving later dubbed it "Colter's Hell," and the name stuck. Colter is the first American citizen known to have entered the park, though historians hotly contest his exact route.

  Over the next 40 years, mountain men and trappers such as Jim Bridger came back with tales of boiling mud, steaming rivers, and petrified trees. Most listeners treated these as dubious rumors. By 1863, people understood the region's basic geography, yet no detailed written account existed.

  In spring 1864, a group of Piegan Blackfeet led the Belgian Jesuit Xavier Kuppens on a tour of the geysers and other major attractions, which they knew well. In 1865, Kuppens described what he had seen to regional political leaders, including Montana Territory Governor Thomas Francis Meagher. Meagher may have suggested preserving the region as a national park, although that conversation was recalled only decades later. Red Cloud's War then interrupted local curiosity from 1866 to 1868.

  In 1833, the painter George Catlin proposed a national park in the American West. He imagined a home where Native Americans could keep their traditional patterns of land use. Washington Irving joined him in 1837, writing that parks could offer "a last refuge to the Indian." Henry David Thoreau followed in 1858 with a "national preserve" for animals, landscapes, and "some even of the hunter race." By the 1860s, after many American Indian Wars and genocides, public opinion favored confining Native Americans to reservations. The national park was then reimagined as pristine wilderness free of human activity. Around 1870, lawyer Cornelius Hedges and Congressman William D. Kelley began writing in support of preserving Yellowstone on those terms, apparently acting on a spoken suggestion from Meagher.

  The Cook-Folsom-Peterson Expedition of 1869 was the first detailed expedition to the area, and it consisted of three privately funded explorers. The Folsom party followed the Yellowstone River to Yellowstone Lake and recorded its findings in a journal. That journal prompted Montana residents to organize the Washburn-Langford-Doane Expedition in 1870, led by surveyor-general Henry Washburn. Members included Nathaniel P. Langford, later known as "National Park" Langford, and Lt. Gustavus Doane, who commanded an army detachment. They spent about a month exploring, collecting specimens, and naming sites of interest. They found that one large geyser erupted every 90 minutes, so they named it Old Faithful. The trip became a media sensation, and many writers predicted that sightseers would follow.

  In 1871, Ferdinand V. Hayden finally explored the region, eleven years after a failed first attempt. His government-sponsored expedition produced the Hayden Geological Survey of 1871, with large-format photographs by William Henry Jackson and paintings by Thomas Moran. The report helped persuade Congress to withdraw the region from public auction. Hayden told the Committee on Public Lands that Yellowstone needed immediate protection. He warned of "vandals who are now waiting to enter into this wonder-land." Those same vandals, he said, would "in a single season despoil, beyond recovery, these remarkable curiosities." Keeping them out would fall to a man from the Washburn expedition.

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• 4. Guardians and Exclusion

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  Nathaniel P. Langford became Yellowstone's first superintendent in 1872, but Congress gave him no salary, no funding, and no staff. Local mining and logging interests opposed the park, so he could make no improvements. He still grasped the danger of pollution and poaching. His first annual report correctly predicted that the park would become internationally famous.

  Soldiers had their own plans for the new park. In 1875, Colonel William Ludlow, who had explored parts of Montana under George Armstrong Custer, was ordered to survey it for fort sites. In those early years, the park also served as a base from which the Army planned raids into Sioux territory in the Black Hills. In April 1877, Philetus Norris replaced Langford, and crises with neighboring tribes arrived quickly.

  During the 1877 Nez Perce War, Nez Perce fleeing the Army took nine park visitors captive, and two people were killed in skirmishes. In the 1878 Bannock War, the Bannock asserted rights over the Great Bannock Trail and raided a United States Geological Survey party. They captured livestock without injuring anyone. Norris responded by cutting a military trail from Mammoth through Obsidian Cliffs down to the Upper Geyser Basin. After the Sheepeater Indian War of 1879, he built a fort to keep Native Americans out of the park. He did praise the comparatively friendly relations the Crow had with park officials, and he urged Congress to give them land north of the park boundary.

  Native Americans were effectively shut out during the 1870s and 1880s, although under a half-dozen tribes had used the area seasonally. The only year-round residents were small bands of Eastern Shoshone known as Sheepeaters. They left under an 1868 treaty in which they gave up their lands but kept the right to hunt in Yellowstone. The United States never ratified that treaty. It refused to recognize the claims of the Sheepeaters or of any other tribe that had used Yellowstone.

  In 1880, Harry Yount became the park's gamekeeper, charged with controlling poaching and vandalism. He is regarded as the first national park ranger. Yount had spent decades exploring the mountain country of present-day Wyoming, including the Grand Tetons, after joining Hayden's Geological Survey in 1873. Yount's Peak, at the head of the Yellowstone River, carries his name. Even so, Norris and the three superintendents after him never received enough staff or resources.

  Poaching and destruction continued until the Army reached Mammoth Hot Springs in 1886 and built Camp Sheridan. Over the next 22 years, as soldiers raised permanent structures, it was renamed Fort Yellowstone. On the 7th of May 1894, the Boone and Crockett Club succeeded in carrying through the Park Protection Act, which saved the park. The club worked through men including George G. Vest, Arnold Hague, William Hallett Phillips, W. A. Wadsworth, Archibald Rogers, Theodore Roosevelt, and George Bird Grinnell. The Lacey Act of 1900 then gave officials legal support for prosecuting poachers.

  With money and manpower finally in hand, the Army wrote its own regulations, which allowed public access while protecting wildlife and natural resources. The National Park Service, created in 1916, adopted many of those management principles. The Army handed control to the Park Service on the 31st of October 1918, after three decades in charge.

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• 5. Roads and Crowds

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  Only 300 people visited Yellowstone in 1872. By 1883 the number was 5,000, after the Northern Pacific Railroad built a station at Livingston, Montana, as a gateway to the northern entrance. A spur line finished that autumn ran from Livingston to Cinnabar, where travelers took stagecoaches to Mammoth. In 1902 the line was extended to Gardiner station, where passengers again switched to stagecoach. A Chicago, Burlington & Quincy connection via Cody opened in 1901. A Union Pacific link to West Yellowstone followed in 1908, and a Milwaukee Road line to Gallatin Gateway near Bozeman came in 1927. By World War II, rail visitation had fallen considerably. Regular service stopped around the 1960s, though special excursions continued into the early 1980s.

  Automobiles were admitted in phases starting in 1915, and by then 1,000 cars a year were entering the park. They clashed with horses and horse-drawn transport, and horse travel on roads was eventually prohibited. The park had been served mostly from the north entrance, but cars now arrived from every direction. Officials built new facilities at the west, south, and northeast entrances between 1924 and 1935.

  The Civilian Conservation Corps, a New Deal relief agency for young men, worked in Yellowstone from 1933 to 1942. Its crews planted trees, built campgrounds and trails, reduced fire hazards, and fought fires. They built most of the early visitor centers and campgrounds and the park's current road system.

  World War II cut tourist travel sharply, staffing was reduced, and many facilities fell into disrepair. By the 1950s, visitation had soared, and officials launched Mission 66 to modernize and expand facilities. It was meant to finish by 1966, honoring the 50th anniversary of the National Park Service. Its buildings broke from the log cabin tradition with modern styling. Most construction in the late 1980s returned to traditional designs, as did the Canyon Village visitor center, which opened in 2006.

  Since the mid-1960s, at least 2 million tourists have come in almost every year. The ten years from 2007 to 2016 averaged 3.5 million visitors, and 2016 set a record of 4,257,177. In 2023, 4.5 million people beat that mark. July is the busiest month. At peak summer levels, 3,700 concessionaire employees work in the park. They run nine hotels and lodges with 2,238 rooms and cabins, plus gas stations, stores, and most campgrounds. Another 800 people work for the National Park Service permanently or seasonally.

  The park has 310 miles of paved roads and five entrances, and no public transportation inside it. From early November to mid-April, wheeled vehicles are barred from every road except the one from Gardiner, Montana, to Cooke City, Montana. Guided snowmobile and snow coach tours operate under quotas set by the National Park Service. In summer, traffic jams from road construction and from people stopping to watch wildlife can cause long delays.

  From 2007 to 2023-74 deaths were recorded in the park. Driving caused over 45% of them. Hiking, climbing, and walking accounted for 38%, often on trails or near geothermal areas. Water activities such as fishing, swimming, and boating caused 16%. Around the thermal features, wooden and paved trails have been built for visitor safety, and most of those areas are accessible to people with disabilities.

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• 6. Volcano Underfoot

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  The Yellowstone Caldera measures 45 by 28 miles, and a cataclysmic eruption 640,000 years ago carved it. That eruption released more than 240 cubic miles of ash, rock, and pyroclastic material and deposited the Lava Creek Tuff. The cause is the Yellowstone hotspot, where a section of the North American plate has been drifting northeast over a massive mantle plume. It is the largest volcanic system in North America, and worldwide only the Lake Toba Caldera on Sumatra rivals it. Beneath the park sits what is estimated to be one connected magma chamber, about 37 miles long, 18 miles wide, and 3 to 7 miles deep.

  The most violent known eruption came 2.1 million years ago. It ejected 588 cubic miles of material and formed the Huckleberry Ridge Tuff and the Island Park Caldera. A smaller eruption 1.3 million years ago threw out 67 cubic miles, forming the Henry's Fork Caldera and the Mesa Falls Tuff. Each of the three climactic eruptions blanketed much of central North America in ash that fell many hundreds of miles away. The ash and gases probably affected world weather and led some species, mostly in North America, to go extinct.

  About 160,000 years ago, a smaller caldera-forming eruption made the caldera that holds the West Thumb of Yellowstone Lake. Between 640,000 and 70,000 years ago, 80 eruptions of lava nearly filled the main caldera. Some were rhyolitic, as seen at Obsidian Cliffs, and some were basaltic, as seen at Sheepeater Cliff. The gaps between the last three cataclysmic eruptions ranged from 600,000 to 800,000 years. Three events are too few to predict the next one.

  The Grand Canyon of the Yellowstone shows the lava layers most clearly, because the river keeps carving into the ancient flows. Its V-shaped profile points to river erosion rather than glaciers. The Lower Falls of the Yellowstone River drop 308 feet, the highest of the park's 290 waterfalls of at least 15 feet.

  Yellowstone has 1,000 to 3,000 small earthquakes every year, almost all too faint for people to feel. About two-thirds occur between Hebgen Lake and the caldera, along a buried fracture zone left by the eruption 2.1 million years ago. In 1959, a 7.2 magnitude earthquake struck just outside the northwest boundary. A landslide partly collapsed a dam on Hebgen Lake and blocked the river below, creating Earthquake Lake. Twenty-eight people died. Inside the park, some northwestern geysers erupted, cracks in the ground gave off steam, and some clear hot springs turned muddy. Six earthquakes of magnitude 6 or greater have been recorded in historical times. On the 30th of March 2014, a magnitude 4.8 quake near Norris Basin was the largest since the 22nd of February 1980.

  Old Faithful sits in the Upper Geyser Basin, alongside Castle, Lion, Beehive, Grand, Giant, and Riverside geysers. Grand is the tallest predictable geyser in the world, and Giant is the most voluminous. Steamboat Geyser, in the Norris Geyser Basin, is the tallest active geyser anywhere. A study completed in 2011 found that at least 1,283 geysers have erupted in Yellowstone, with an average of 465 active in any given year. The park holds at least 10,000 geothermal features, counting geysers, hot springs, mudpots, and fumaroles. Two-thirds of the world's geysers are here. In 1898, John Muir wrote of geysers rushing up as "white torrents of boiling water and steam, like inverted waterfalls."

  In May 2001, the U.S. Geological Survey, the park, and the University of Utah created the Yellowstone Volcano Observatory for long-term monitoring. In 2003, changes at the Norris Geyser Basin closed some trails. New fumaroles appeared, and several geysers grew more active and hotter. Some became so hot that they turned into purely steaming features and could no longer erupt normally. A multiyear survey mapping the floor of Yellowstone Lake found a structural dome that had been uplifted at some earlier time. Research indicated no immediate threat of eruption, since the uplift may have formed long ago and no temperature rise was found near it. In July 2024, a hydrothermal explosion occurred in Biscuit Basin.

  In the hot water, bacteria form mats of bizarre shapes made of trillions of organisms. Flies and other arthropods live on the mats even in the bitter cold of winter. One resident, Thermus aquaticus, makes the enzyme Taq polymerase, which is easily replicated in the lab and used in the polymerase chain reaction to copy DNA. Research on Yellowstone thermophiles has also helped develop virus tests and new kinds of biodegradable plastic. In 2016, researchers from Uppsala University reported Hadesarchaea in the Culex Basin, organisms that convert carbon monoxide and water to carbon dioxide and hydrogen.

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• 7. Wolves, Bison, and Bears

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  In 1914, Congress appropriated money for "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out the order, and by 1926 they had killed 136 wolves. The practice continued until the National Park Service ended it in 1935, and wolves were virtually gone from Yellowstone by then. The Endangered Species Act of 1973 later listed the wolf among its first mammals. Coyotes took over as the top canine predator, but they cannot bring down large animals. Without an apex predator, lame and sick megafauna increased markedly.

  By the 1990s, the federal government had reversed its view. In a controversial decision, the U.S. Fish and Wildlife Service reintroduced wolves imported from Canada. The effort succeeded, and a 2024 survey counted 9 packs totaling 108 wolves. On the 27th of February 2008, the agency removed the Northern Rocky Mountain wolf population from the endangered species list. Yellowstone's wolves now sit at the core of a larger population linked across the Greater Yellowstone Ecosystem.

  The northern elk herd has dropped enormously since the mid-1990s. Researchers attribute this to wolf predation and to elk moving into forests to evade wolves, which also makes counting harder. Elk still number more than 30,000, the largest population of any large mammal in the park. Scientists at Oregon State University credit the wolves, by changing how elk graze, for the recent recovery of aspen. The southern herd's migration is the largest mammalian migration remaining in the U.S. outside Alaska.

  Bison once numbered between 30 and 60 million across North America. In the park, they numbered fewer than 50 in 1902 and reached 6,000 in 2023, which required a cull of 1,150. About half of Yellowstone's bison have been exposed to brucellosis, a bacterial disease that arrived with European cattle and may cause cattle to miscarry. It has little effect on park bison, and no transmission from wild bison to domestic livestock has been reported. Elk also carry the disease and are believed to have infected horses and cattle.

  Park personnel regularly corral bison back inside the boundary when they wander out. In the winter of 1996-1997, 1,079 bison that had left the park were shot or sent to slaughter. Animal rights activists call the practice cruel. Ecologists note that the bison are traveling to seasonal grazing lands within the Greater Yellowstone Ecosystem that have been converted to cattle grazing, some in national forests leased to private ranchers. APHIS has stated that vaccinations and other means could eliminate brucellosis from the herds.

  An estimated 700 grizzly bears live in the Greater Yellowstone Ecosystem, with about 150 living wholly or partly inside the park. The Fish and Wildlife Service listed the grizzly as threatened on the 28th of July 1975 and removed it from the list in 2007. A federal district judge overturned that decision in 2009. The bear came off the list again in 2017. In September 2018, another district judge ruled that its protections must be restored in full, finding the agency mistaken.

  Black bears became a park symbol after visitors began interacting with them in 1910. Feeding and close contact have been banned since the 1960s to reduce the bears' desire for human food. Yellowstone is one of the few places in the United States where black bears can be seen coexisting with grizzlies.

  Yellowstone cutthroat trout, a fish highly sought by anglers, have faced lake trout in Yellowstone Lake, an ongoing drought, and whirling disease, which kills young fish. Since 2001, all native sport fish caught in park waters must be released. The cougar population is estimated at only 25 across the park. In 2003, observers followed the tracks of a female lynx and her cub for over 2 miles, and tests of evidence confirmed them as lynx. No one saw the animals. Lynx have not been seen in Yellowstone since 1998, though DNA from hair collected in 2001 confirmed that lynx had at least passed through.

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• 8. Fire and Flood

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  Lightning ignites about thirty-five natural forest fires in Yellowstone each year, and people start another six to ten, usually by accident. Plants have adapted to the flames. Douglas-fir bark is thick enough to shield the inner tree. Lodgepole pine, the most common tree in the park, has cones that open only in the heat of a fire, which melts the resin holding the seeds. Aspen sprout from roots insulated by soil. The National Park Service estimates that under natural conditions grasslands burned every 20 to 25 years and forests about every 300 years.

  Until the 1970s, every fire was suppressed, because land managers saw fire as purely destructive. That left dead and dying forests that later fueled fires much harder to control. The 2014 Fire Management Plan lets natural fires burn if they pose no immediate threat to lives and property. Over the last 30 years, more than 300 natural fires have been allowed to burn. Three staffed lookout towers watch for smoke, and the easiest to reach sits atop Mount Washburn.

  The spring of 1988 was wet, and the summer that followed became the driest year on record to that point. The wet spring grew plenty of grass, and it dried into tinder. Between the 15th and the 21st of July 1988, fires spread from 8,500 acres across the wider Yellowstone region to 99,000 acres on park land alone. The single worst day was the 20th of August, when more than 150,000 acres burned. Seven large fires caused 95% of the 793,000 acres burned over the following months. More than one-third of the park burned.

  The fight drew in 25,000 firefighters and U.S. military forces and cost 120 million dollars. Snow in winter finally put out the last flames. The fires destroyed 67 structures, and two people associated with the firefighting died. No civilians were killed. Media reports at the time suggested heavy losses among animals, but surveys found that only about 345 elk, out of an estimated 40,000-50,000, had died. The toll also included 36 deer, 12 moose, 6 black bears, and 9 bison. By 1992, Yellowstone had adopted a new plan with stricter guidelines for natural fires.

  On the 21st of July 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness and hit the park. Rated F4, with winds estimated at 207 to 260 miles per hour, it left a path 1 to 2 miles wide and 24 miles long. It leveled 15,000 acres of mature pine forest. The coldest temperature on record in the park is -66 degrees Fahrenheit, set in 1933, and the record high is 99 degrees, set in 2002.

  In June 2022, record rainfall and rapid snowmelt flooded Yellowstone. The park closed entrances and evacuated visitors. The Yellowstone River rose to 13.88 feet, breaking the 1918 record of 11.5 feet. The Lamar River reached 16.7 feet, beating a 1996 record of 12.15 feet. Roads and bridges failed, and electricity, water, and wastewater systems were damaged. The park partially reopened on Wednesday the 22nd of June after a 9-day closure. To limit nearly one million visitors per month in summer, it temporarily restricted entry by license plate. The northeast entrance near Cooke City reopened on the 15th of October, and the north entrance by Gardiner reopened on the 30th of October, two days ahead of schedule.

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