Centennial Valley is located in Montana’s Beaverhead and Madison Counties. Its high-elevation 385,000 acres are north and east of the Continental Divide along the Montana-Idaho border. The Centennial Mountains are over 10,000 feet in elevation rising 3,300 feet above the valley floor. The mountains are the headwaters to the Missouri River. Access into the valley from the west is via the Monida exit on Interstate I15. On the east, visitors can enter from the West Yellowstone area via Henry Lake and Red Rock Pass.
Centennial Valley is a critical part of the “Montana Natural Heritage Program.” It is one of the most significant landscapes in Montana because of its intact ecological systems, expansive wetlands, diverse wildlife and flora, and unique concentrations of rare species. The Centennial Mountains on the south side of the valley rise dramatically above the valley floor. The foothills of the Gravelly Mountain range are on the north.
The valley has the largest wetland complex in the Greater Yellowstone Ecosystem. The Red Rock River flows through the broad and flat valley floor, feeding the Upper and Lower Red Rock Lakes. Sagebrush, grasslands, and lush willow riparian areas characterize the uplands on the valley floor.
Often called the most beautiful wildlife refuge in the United States, Red Rock Lakes National Wildlife Refuge is a high-elevation mountain wetland-riparian area. Red Rock Creek flows through the upper end of the Centennial Valley within which the Refuge lies, creating the impressive Upper Red Rock Lake, River Marsh, and Lower Red Rock Lake marshlands. The rugged Centennial Mountains border the Refuge on the south, catching the snows of winter that replenish the Refuge’s lakes and marshes.
Mountains and Wildlife
The Centennial Mountains are one of the few ranges of the Rockies that run from east to west. Covered mostly by Douglas fir, they provide a critical high elevation corridor for a variety of wildlife, including wolves, bear, and wolverines. The Centennial Valley’s diverse environment supports over 260 species of birds, including the peregrine falcon, bald eagle, sand hill cranes, sage grouse, and Trumpeter Swans. Elk, moose, pronghorn antelope, bear, mule and white-tailed deer, and red fox populate the valley’s varied ecosystems. Streams are home to the Arctic grayling and westslope cutthroat trout.
The Centennial Valley’s history was well known to the Shoshone-Barnock, the Nez Perce, and other nomadic tribes. Euro-American settlers arrived in 1876 to homestead. The long winters, great distances to market, and small land parcels made life extremely difficult. Few survived the Great Depression in the 1930s. Centennial Valley is also the historic stagecoach route from Monida into West Yellowstone. In 1902 alone it carried over 12,000 passengers into the National Park. This grand era of stagecoach travel ended in 1917 with the entrance of the touring car.