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Press Release: Palos Preserves Named the World’s Largest Urban Night Sky Place

Forest Preserves of Cook County and Adler Planetarium earn the Urban Night Sky Place designation, awarded by the International Dark-Sky Association, for a 6,662-acre site in Southwest Cook County

August 25, 2021—The Forest Preserves of Cook County’s Palos Preserves has been designated the largest Urban Night Sky Place in the world by the International Dark-Sky Association (IDA). About four times more stars are visible in the night sky over the site than in the City of Chicago as measured by Adler Planetarium, which partnered with the Forest Preserves to submit the site’s application.

The Palos Preserves, historically known as Mt. Forest Island, is part of the largest area of protected natural land in Cook County. The Urban Night Sky Place houses only four buildings in its 6,662 acres, and satellite radiance data show that the region emits nearly 1000 times less light than downtown Chicago. Forest Preserves sites are closed at sunset, so visitors who want to enjoy the night at this Urban Night Sky Place should keep an eye out for the Preserves’ guided nighttime programming in Palos Preserves.

“People know the Palos Preserves for its extensive trail system and the natural wonder of the hills, bluffs, woodlands and wetlands. I’m pleased that with this Urban Night Sky designation, the site is also recognized as a location that preserves the night. The many species of plants, insects, birds and other animals that call the Palos Preserves home benefit from the absence of disturbing artificial lighting,” said Arnold Randall, the general superintendent of the Forest Preserves.

To measure and document the light levels in Palos Preserves, the Adler Planetarium worked with their teen interns to use specially designed cameras, built by students and volunteers at the Adler, across Chicago and in the Preserves last summer to quantify the nighttime sky in the region. The students also used satellite data and images from astronauts on board the International Space Station for the application. The Adler also provided guidance in a light management plan that was initiated by the Forest Preserves as part of the Dark Skies application, which reduced light levels at the Preserves’ buildings and parking lots with a combination of timers, shielded fixtures and night sky friendly LED lighting.

“For the entire history of life on Earth, dark nights followed sunlit days. In a little more than a century we’ve altered that natural pattern by illuminating our nights. Living in and around Chicago we’ve grown accustomed to always having bright lights in view. The chance of experiencing a natural, dark night—as it was for eons—is now too rare. It’s difficult to express the peaceful, natural beauty one can experience within the Palos Preserves’ pristine nights. This designation is a recognition of the value it offers to everyone in the region,” said Ken Walczak, Senior Manager for Far Horizons at the Adler Planetarium.

The IDA’s International Dark Sky Places program was founded in 2001 to encourage communities, parks and protected areas around the world to preserve and protect dark sites through responsible lighting policies and public education. There are more than 170 Dark Sky Places across the world, including three in the Urban Night Sky Place category. IDA designates the places following a rigorous application process requiring applicants to demonstrate robust community support for dark-sky protection, a commitment to stewardship of the nighttime environment and designation-specific program requirements.

“The Forest Preserves’ commitment to understanding the principles of responsible outdoor lighting, engaging in community outreach, and providing access to this natural resource for the residents of the Chicago area all serve as commendable examples of what UNSPs can offer,” stated Ruskin Hartley, Executive Director of IDA.

The Forest Preserves and Adler Planetarium will continue to partner in the Palos Preserves around the Urban Night Sky Place, particularly for fun and educational programs and events like stargazing nights, night hikes, owling and light pollution awareness programs.


About the Forest Preserves of Cook County
Don’t you sometimes just want to escape? Explore the natural beauty of Cook County for an hour, a day or even a night. When you’re surrounded by 70,000 acres of wild and wonderful there’s no better place to feel free.