Teton County, Wyoming, was certified as an International Dark Sky Community on April 11th, 2025, by DarkSky International. This achievement culminates a decade of collaborative work between the Town of Jackson, Teton County, Wyoming Stargazing, Dr. John Barentine, Dr. Bryan Boulanger, and several other stakeholders. Teton County is now the world’s first county to be designated as an International Dark Sky Community (IDSC).
“The significance of this certification effort cannot be overstated. Teton County covers a vast amount of land with both private and public ownership, so this recognition awards those with all degrees of interest in conserving not only the land but also the sky of the region,” said Michael Rymer, DarkSky International Program Associate. “Wyoming Stargazing showed tremendous consistent leadership throughout this project, and with cooperation from other organizations and professionals in addition to the unending commitment from the town of Jackson and the county, it is no wonder they achieved an International Dark Sky Community certification.”
Teton County is located in the northwest corner of Wyoming, U.S. It has a total area of 10,920 square kilometers (sq km), of which 10,350 sq km (94.8% of the total area) is land and 570 km (5.2% of the total area) is water. It is the 12th largest county in Wyoming by total area. Federally managed public lands comprise 97 percent of county territory, including two U.S. National Parks, Yellowstone and Grand Teton. Also, within its boundaries are parts of three U.S. National Forests (Bridger-Teton, Caribou-Targhee, and Shoshone), the John D. Rockefeller Memorial Parkway, and the U.S. National Elk Refuge.
Teton County is defined by two major geologic provinces. In the north, the Yellowstone area includes the largest volcanic system in North America. The landscape is dominated by the Yellowstone Caldera, created in a cataclysmic eruption 640,000 years ago that ejected more than 1,000 cubic kilometers (240 cubic miles) of ash, rock, and pyroclastic material. South of Yellowstone, Grand Teton National Park contains some of the oldest rocks in any U.S. National Park, dating to some 2.7 billion years before present. Two and a half billion years ago, these oldest rocks were intruded by igneous granitic rocks, now seen in the central Teton Mountains, including Grand Teton (elevation 4,200 meters above sea level) and the nearby peaks.
Spanning much of southern Teton County, Jackson Hole is a feature known as a graben, which forms as the Earth’s crust pulls apart locally and the central portion of the active area collapses downward. The valley is situated east of the Teton Range and is displaced downward some 9,000 meters (30,000 feet) from its original position. Erosion has since filled Jackson Hole with enough sediment to reduce the vertical exaggeration to only 2,300 meters (7,700 feet). Glaciers carved out basins at the foot of the Teton Range, which subsequently filled with water to form the lakes of today’s Grand Teton National Park.
Those glaciers retreated northward across what is now Teton County around 14,000 years ago. The earliest archeological evidence of people in the vicinity dates back to about 11,000 years ago, near the conclusion of the last Ice Age. The material culture of the prehistoric peoples of the area consists of a variety of stone projectile points and ceramics. Evidence of occupation is also found in the remnants of stone-lined roasting pits, suggesting lifeways oriented around seasonal availability of food sources. Occupation was always temporary and may have occurred even during the harsh weather of the winter months. The descendants of these people, including the Bannock, Blackfoot, Crow, Eastern Shoshone, Gros Ventre, Mountain Shoshone, Nez Perce, and Northern Arapaho, were distributed throughout the area when non-Native colonizers arrived. Today, over two dozen Native American tribes are recognized as having prehistoric as well as historical connections to the lands now encompassed by Teton County.
Teton County lies at the core of an area including all of the land designations listed above that are collectively known as the Greater Yellowstone Ecosystem (GYE). The GYE is recognized as the largest intact ecosystem in the contiguous United States. As such, it is home to abundant mammalian species, including bison, moose, elk, deer, pronghorn, grizzly bears, black bears, wolves, wolverines, mountain lions, and 60 other species of mammals. There are also over 300 species of birds, 12 species of native fish, six species of reptiles, five species of amphibians, and over 1,000 species of plants that utilize the GYE.
The history of this IDSC designation begins in the winter of 2013 when Wyoming Stargazing began hosting weekly public stargazing programs throughout the year and solar astronomy programs in the summer to share Wyoming’s extraordinary sky with the public, as well as to bring attention to the problems associated with light pollution. Soon thereafter, Wyoming Stargazing was contacted by a local night sky and wildlife photographer named Mike Cavaroc. He helped Wyoming Stargazing create the Save Our Night Skies Campaign to reduce local light pollution and work towards IDSC certification for the Town of Jackson and all of Teton County. Wyoming Stargazing approached Teton County and the Town of Jackson to update the Exterior Lighting Standards. Some revisions were made, but none that applied to public lighting.
In August of 2021, Wyoming Stargazing hosted the first annual Lights Out Challenge in Jackson Hole. The Community Foundation of Jackson Hole awarded a grant to Wyoming Stargazing 2022 to rewrite the Teton County and Town of Jackson Exterior Lighting Standards. Major revisions were made with the help of Dr. John Brentine, including applicability to public lighting, which made municipal Teton County and the Town of Jackson qualified to apply for dark sky certification. Then, in 2023, Dr. Bryan Biulanger conducted comprehensive exterior lighting inventories of the Town of Jackson, Teton County, and Grand Teton National Park, leading, then, to Dr. John Barentine and Wyoming Stargazing preparing the application for IDSC status for Teton County during the Fall and Winter of 2024-2025. Meanwhile, during the application review by DarkSky International, Wyoming Stargazing created a Dark Sky Friendly Lighting Certification Program in order to assist homeowners, rental property managers, and businesses in making their outdoor lighting dark-sky compliant.
“The stars are literally etched into our DNA,” said Samuel Singer, the Executive Director of Wyoming Stargazing. “If dark night skies ever disappear, we will have lost a part of what it means to be human. IDSC certification is our commitment to prevent that from happening.”
Byran Gleason, an architect who lives and works in Teton County, added, “A Dark Sky Community certification enhances our community’s reputation as a leader in conservation and responsible development. As a gateway to Grand Teton and Yellowstone National Parks, Teton County is already a symbol of environmental stewardship. Achieving this certification further demonstrates our commitment to safeguarding the very qualities that make our region so special—our connection to nature, our dedication to sustainability, and our respect for the land that sustains us.”
“This community commitment to ensuring future generations of park visitors and county residents all have access to the beauty Wyoming skies offer in the night is something we are all proud to be a part of,” said Grand Teton National Park Superintendent Chip Jenkins.
Teton County IDSC is an important stepping stone to a more ambitious goal: the accreditation of a very large region of the states of Montana, Wyoming, and Idaho as an International Dark Sky Reserve. This designation would affect one of the few remaining geographically large regions of near-pristine darkness in the contiguous United States. There are strong arguments for doing so, the least of which is that it would significantly bolster efforts to protect an ecologically significant region of the world: the Greater Yellowstone Ecosystem (GYE).
About the International Dark Sky Places Program:
Founded in 2001, the International Dark Sky Places Program is a non-regulatory and voluntary program encouraging communities, parks, and protected areas worldwide to preserve and protect dark sites through effective lighting policies, environmentally responsible outdoor lighting, and public education. When used indiscriminately, artificial light can disrupt ecosystems, impact human health, waste money and energy, contribute to climate change, and block our view and connection to the universe. Teton County now joins more than 240 Places that have demonstrated robust community support for dark sky advocacy and strive to protect the night from light pollution. Learn more by visiting https://darksky.org/what-we-do/international-dark-sky-places/.
About DarkSky International:
The mission of DarkSky is to preserve and protect the nighttime environment and our heritage of dark skies through environmentally responsible outdoor lighting. Learn more at darksky.org
Click here to view the original press release from DarkSky
Cover Photo taken by More Than Just Parks