The Centennial Mountains on the eastern edge of Idaho are a rich landscape, home to essential waters and wildlife. The crest of the Centennials forms the Continental Divide (and Idaho/Montana state border), so named because it’s the dividing line between waterways bound for the Pacific Ocean to the west and the Gulf of Mexico to the south and east.

The Centennial Range is a key corridor for wildlife movement, connecting the Greater Yellowstone Ecosystem with the rest of the northern Rocky Mountains. This important linkage provides key migration pathways and habitat for grizzly bears, lynx, bighorn sheep, wolverine, and many other species.

The headwaters of Idaho’s Snake River and its aquifer, which provides drinking water for 300,000 Idahoans, are found high in the Centennial range. 

The Centennials are located in Idaho’s remote Clark County, the least populous county in the state, and provide abundant recreational opportunities for hikers, wildlife viewers, campers, motorized users, and nature lovers of all ages. Locals and visitors rely on the Centennials for solace and adventure. 

But this unique part of Idaho is under threat. A proposed gold exploration project on the south slope of the Centennials near Kilgore, Idaho would threaten the key ecological resources of the range; disrupt the wildlife corridor; impact grizzly bears, Yellowstone cutthroat trout, Columbia spotted frogs, and whitebark pines; and risk contaminating a critical water source for people, farmers, and ranchers. The Idaho Conservation League works to ensure that mining activities don’t threaten human health, special places, or Idaho’s clean water. 

The Centennials are a special place, but don’t take our word for it. We encourage you to explore the Centennial Range and become inspired to help us protect this wonderful and wild Idaho treasure. These two adventures will be sure to show you why ICL is working to protect the lands, waters, and wildlife of the Centennial Mountains. 


Centennial Mountains: Kilgore Project Area Tour

Tony H., an ICL member and volunteer from Idaho Falls, shared with us his favorite motor vehicle loop that explores the Kilgore project area


Take a hike to Aldous and Hancock Lakes

If you’re looking to explore the Centennial Range on foot, the hike to Aldous and Hancock lakes is a kid-friendly adventure along the Continental Divide with options to extend your hike into more rugged territory.