It was designated on December 18, 2017, and is the first gold-tier dark sky preserve in the United States.

The area includes the city of Ketchum, Idaho which was separately designated a "Dark Sky Community" in 2017.

[1] Local communities and federal authorities collaborated in the designation; the governments will take measures such as shielding street lights to preserve the area's dark sky;[5][6] Ketchum has had a dark sky ordinance since 1999, and Sun Valley, also in the reserve, has its own local ordinance.

[7][8] The U.S. Forest Service, which manages much of the land in the area, will post informational signs about the dark sky reserve, and has said it will reduce light pollution from its buildings; compliance by individuals on Forest Service land will be voluntary.

[7] Another dark sky certification effort was under way in 2017 about 80 miles (130 km) away at Bruneau Dunes State Park, which hosts a public astronomical observatory.