At least 11,000 years ago
A Clovis point from this period was made from obsidian obtained at Obsidian Cliff.
10,000 years ago
Sites all over the park yield paleoindian artifacts, particularly concentrated around Yellowstone Lake. Clovis peoples hunted large game and gathered resources across North America.
9,350 years ago
A site on the shore of the Yellowstone Lake has been radiocarbon dated to 9,350 years ago. People seem to have occupied this site for short seasonal periods.
9,000 years ago
9,000 years ago until 1,000 common era (CE), people leave traces of camps on the shores of Yellowstone Lake. Note: CE = Common Era (replaces AD)
8,000 years ago
Vegetation similar to what we find today begins to appear. This period is characterized by use of large side-notched projectile points and atlatl technology.
3,000 years ago
Bison jumps and corrals begin to be used in the Rocky Mountain region. Oral histories of the Salish place their ancestors in the Yellowstone area.
1,500 years ago
Bow and arrow begins to replace atlatl (throwing spear). Sheep traps begin to be used in the mountains.
Oral histories of the Kiowa place their ancestors in the Yellowstone area from this time through the 1700s.
Little Ice Age begins.
North American tribes in the southwest begin acquiring horses in the mid- to late 1600s. Ancestors of the Crow may have come into the Yellowstone ecosystem during this time.
Lakota Sioux begin exploring the Yellowstone area.
Late 1700s–1840s CE
Fur traders travel the rivers into the Yellowstone region. Tribes in the Yellowstone area begin using horses.
The Lewis and Clark Expedition passes within 50 miles of Yellowstone.
John Colter first known European-American to visit present-day Yellowstone.
Trapper Osborne Russell encounters Tukudika ("Sheep Eaters") in Lamar Valley.
Little Ice Age ends, climate begins to warm.
First organized expedition attempts but fails to explore the Yellowstone Plateau.
Gold strike northwest of Yellowstone.
Washburn–Langford–Doane Expedition; Old Faithful Geyser named.
First Hayden expedition.
March 1, Yellowstone National Park Protection Act establishes the first national park; first "hotel" in park opens at Mammoth.
First budget for park; Nez Perce (Nee-me-poo) flee US Army through Yellowstone.
Northern Pacific Railroad arrives near Gardiner, MT.
First hotel at Old Faithful opens, known as the Shack Hotel.
The US Army arrives to manage Yellowstone, creating the temporary Camp Sheridan at Mammoth.
First Lake Hotel built.
First National Park Protection Act (Lacey Act) makes it illegal to kill wildlife in the park.
President Theodore Roosevelt dedicates arch at the North Entrance by laying its cornerstone at Gardiner.
Old Faithful Inn opens.
The Antiquities Act provides for the protection of historic, prehistoric, and scientific features on, and artifacts from, federal lands.
Union Pacific train service begins at West Yellowstone.
Private automobiles are officially admitted to the park.
The National Park Service Organic Act establishes the National Park Service.
Private and commercial horsedrawn conveyances banned on park roads.
National Park Service (NPS) takes over management of Yellowstone and the Army leaves.
Horace Albright becomes first NPS superintendent.
President Hoover signs first law changing park’s boundary.
President Hoover expands the park again (by executive order).
Civilian Conservation Corps (CCC) and other government-funded work crews complete work in Yellowstone.
The National Park Service Director’s Order prohibits killing predators.
The Historic Sites Act sets a national policy to “preserve for future public use historic sites, buildings, and objects.”
Much of the park closes for WWII.
Yellowstone receives one million visitors.
First motorized oversnow vehicles allowed in park.
Mission 66 begins in Yellowstone to revitalize lodging, dining, education, and infrastructure.
West of Yellowstone, a 7.5 M earthquake strikes, killing campers in the Custer-Gallatin NF and affecting thermal features and infrastructure in the park.
Leopold Report leads to the last of the bear-feeding dumps closing over the following several years; Robert Reamer-designed Canyon Hotel burns to the ground.
Park sees 2,000,000 visitors for first time.
The thermophile Thermus aquaticus is discovered in a Yellowstone hot spring.
New bear management plan begins, which includes closing open-pit dumps in park.
Overnight winter lodging opens in park and continues yearly.
Grizzly bear listed as threatened species in the lower 48 states.
Public Law 100-443 protects hydrothermal features in national parks from geothermal development on adjacent federal lands; wildfire burns approximately 36% of the park.
Clean Air Act Amendments require air-quality monitoring at sites including Yellowstone, a Class I airshed.
Park sees 3,000,000 visitors for the first time.
Congress enacts a law allowing a percentage of park entrance fees to be kept in the parks.
Wolves are restored to the park.
New World Mine, near park’s northern boundary, halted.
The National Parks Omnibus Management Act is passed.
Interagency Bison Management Plan is adopted by federal, state, and tribal partners.
National Academy of Sciences confirms effectiveness of Ecological Process Management (aka natural regulation).
Yellowstone's grizzly bears removed from federal threatened species list.
Scientific review panel recommends an increase in lake trout removal operations on Yellowstone Lake.
Grizzly bears returned to threatened species list. Bioprospecting final EIS completed; science agenda established for Greater Yellowstone Ecosystem.
Grey wolves removed from the endangered species list in MT, ID, OR, and WA. Remain listed in WY until 2017.
Park sees 4,000,000 visitors for the first time.
National Park Service Centennial.
The Earliest Humans in Yellowstone
Human occupation of this area seems to follow environmental changes of the last 15,000 years.
Many tribes have a traditional connection to this region and its resources.
European Americans Arrive
In the late 1700s, fur traders traveled the Yellowstone River in search of Native Americans with whom to trade.
Expeditions Explore Yellowstone
Formal expeditions mapped and explored the area, leading to the nation's understanding of the region.
Birth of a National Park
Learn about Yellowstone's early days as a national park.
Managing the national park has evolved over time and dealt with some complex issues.
Today's National Park Service
The National Park Service manages over 80 million acres in all 50 states, the Virgin Islands, Puerto Rico, Guam, and American Samoa.
Learn about Yellowstone's story from the earliest humans to today.
Last updated: August 15, 2023