NPS illustration Paleoindian PeriodAt least 11,000 years agoA Clovis point from this period was made from obsidian obtained at Obsidian Cliff. 10,000 years agoFolsom people were in the Yellowstone area as early as 10,900 years ago—the date of an obsidian Folsom projectile point found near Pinedale, Wyoming. Sites all over the park yield paleoindian artifacts, particularly concentrated around Yellowstone Lake. 9,350 years agoA site on the shore of Yellowstone Lake has been dated to 9,350 years ago. The points had traces of blood from rabbit, dog, deer, and bighorn sheep. People probably used this area in the summer while hunting bear, deer, bighorn, and rabbits, and perhaps making tools and clothes and seem to have occupied this site for short, seasonal periods. Archaic Period8,000–1,500 years agoBeginning 8,000 years ago until 1,500 common era (CE), people leave traces of camps on shores of Yellowstone Lake. Note: CE (Common Era) replaces AD. 7,000 years agoVegetation similar to what we find today begins to appear. Projectile points begin to be notched. 3,000 years agoOral histories of the Salish place their ancestors in the Yellowstone area. Artifacts dating to 3,000 years ago have also been discovered on islands in Yellowstone Lake, leading some archeologists to speculate that indigenous peoples used watercraft to travel there. 1,500 years agoBow and arrow begins to replace atlatl (throwing spear); sheep traps (in the mountains) and bison corrals (on the plains) begin to be used in the Rocky Mountain region. 500–1700s CE1400Oral histories of the Kiowa place their ancestors in the Yellowstone area from this time through the 1700s. 1450Little Ice Age begins. 1600sNorth American tribes in the southwest begin acquiring horses in the mid- to late 1600s. Ancestors of the Crow may have come into Yellowstone during this time. 1700sLakota Sioux begin exploring the Yellowstone area. Late 1700s–1840s CELate 1700sFur traders travel the rivers into the Yellowstone region. Tribes in the Yellowstone area begin using horses. 1804–1806The Lewis and Clark Expedition passes within 50 miles of Yellowstone. 1807–1808John Colter likely explores part of Yellowstone. 1820sTrappers return to Yellowstone area. 1834–1835Trapper Osborne Russell encounters Tukudika ("Sheep Eaters") in Lamar Valley. 1850s–1871 CE1850sLittle Ice Age ends, climate begins to warm. 1860First organized expedition attempts but fails to explore the Yellowstone Plateau. 1862Gold strike northwest of Yellowstone. 1869Folsom–Cook–Peterson Expedition. 1870Washburn–Langford–Doane Expedition; Old Faithful Geyser named. 1871First Hayden expedition. 1872–1900 CE1872Yellowstone National Park Protection Act establishes the first national park. 1877Nez Perce (Nee-me-poo) flee US Army through Yellowstone. 1883Northern Pacific Railroad reaches the north boundary of the park. 1886The US Army arrives to administer the park. They stay until 1918. 1894Poacher Ed Howell captured; National Park Protection Act (Lacey Act) passed. 1901–1917 CE1903President Theodore Roosevelt dedicates arch at the North Entrance by laying its cornerstone at Gardiner. 1906The Antiquities Act provides for the protection of historic, prehistoric, and scientific features on, and artifacts from, federal lands. 1908Union Pacific train service begins at West Yellowstone. 1915Private automobiles are officially admitted to the park. 1916The National Park Service Organic Act establishes the National Park Service. 1918–1939 CE1918US Army turns over park management to the National Park Service. 1929President Hoover signs first law changing park’s boundary. 1932President Hoover expands the park again (by executive order). 1933Civilian Conservation Corps established, works in Yellowstone through 1941. 1934The National Park Service Director’s Order prohibits killing predators. 1935The Historic Sites Act sets a national policy to “preserve for future public use historic sites, buildings, and objects.” 1940–1959 CE1948Yellowstone receives one million visitors. 1949Nineteen snowplane trips carry 49 passengers into the park in winter. 1955Mission 66 initiated. The first concession-run snowcoach trips carry more than 500 people into the park in winter. 1959Magnitude 7.5 M earthquake strikes on August 17 west of Yellowstone, killing campers in Gallatin National Forest and affecting infrastructure, and thermal areas in the park. 1960–1975 CE1963The Leopold Report is issued. 1966The thermophile Thermus aquaticus is discovered in a Yellowstone hot spring. 1970New bear management plan begins, which includes closing open-pit dumps in park. 1971Overnight winter lodging opens in park and continues yearly. 1975Grizzly bear listed as threatened species in the lower 48 states. 1976–2000 CE1988Public Law 100-443 protects hydrothermal features in national parks from geothermal development on adjacent federal lands; Summer of Fire: more than 790,000 acres affected by fires in Yellowstone. 1991Clean Air Act Amendments require air quality monitoring at sites including Yellowstone, a Class I airshed. 1994Congress enacts a law allowing a percentage of park entrance fees to be kept in the parks. 1995Wolves are restored to the park. 1996Federal buyout of gold mine on Yellowstone’s northeast border is authorized. 1998The National Parks Omnibus Management Act is passed. 2000Interagency Bison Management Plan is adopted by federal, state, and tribal partners. 2001 CE–Present2002National Academy of Sciences confirms effectiveness of Ecological Process Management (aka natural regulation). 2007Yellowstone's grizzly bears removed from federal threatened species list. 2008Scientific review panel recommends an increase in lake trout removal operations on Yellowstone Lake. 2009Grizzly bears returned to threatened species list. Bioprospecting final EIS completed; Science agenda established for Greater Yellowstone Ecosystem. 2011Grey wolves removed from the endangered species list in MT, ID, OR, and WA. Remain listed in WY until 2017. 2016National Park Service Centennial. 
The Earliest Humans in YellowstoneHuman occupation of this area seems to follow environmental changes of the last 15,000 years. 
Historic TribesMany tribes have a traditional connection to this region and its resources. 
European Americans ArriveIn the late 1700s, fur traders traveled the Yellowstone River in search of Native Americans with whom to trade. 
Expeditions Explore YellowstoneFormal expeditions mapped and explored the area, leading to the nation's understanding of the region. 
Birth of a National ParkLearn about Yellowstone's early days as a national park. 
Modern ManagementManaging the national park has evolved over time and dealt with some complex issues. 
Today's National Park ServiceThe National Park Service manages over 80 million acres in all 50 states, the Virgin Islands, Puerto Rico, Guam, and American Samoa. 
Park HistoryLearn about Yellowstone's story from the earliest humans to today. |
Last updated: August 4, 2021