The Centennial Mountains are the southernmost sub-range of the Bitterroot Range in the U.S. states of Idaho and Montana.

The range extends east from Monida Pass along the Continental Divide to Henrys Fork 48 km (30 mi) NNW of Ashton, Idaho; bounded on the west by Beaver Creek, on the north by Centennial Valley and Henrys Lake Mountains, on the east by Henrys Lake Flat, and on the south by Shotgun Valley and the Snake River Plain.

[1] They are one of only a few ranges within the Rocky Mountains that trend west to east, and the Continental Divide runs along their ridge line.

[2] The Western Centennial Mountains extends west from the Eastern Centennial Mountains along the Continental Divide to Monida Pass, 25 mi NE of Dubois, Idaho; Snake River Plain, on the north by Centennial Valley, and the east by a line connecting Odell Creek and an unnamed tributary, in Montana, to Ching Creek in Idaho.

[4] Grizzly bears inhabit the area, as nearly all species indigenous to the Greater Yellowstone Ecosystem are present.