- established February 26, 1917, from Boise and Idaho counties, with its county seat at Cascade
- named for the outstanding topographical feature of the area
Fur trappers were the first white men in the area but permanent settlement did not take place until the 1880s when livestock ranchers moved into the area. Discovery of gold at Thunder Mountain in 1894 brought hundreds of miners to the county. First permanent communites were Van Wyck and Crawford (1882) and Lardo (1886), later to become McCall. Cascade absorbed the populations of Van Wyck and Crawford when it became a station on the railroad line 1913. (see post office history)
The majority of the county is public land, under the jurisdiction of the U.S. Forest Service. The Cascade Ranger District, Boise National Forest, covers the southern portion of the county and the McCall Ranger District, Payette National Forest, covers the northern portion. A large section of the Idaho Primitive Area is in the county.
Valley County towns, post offices and communites
- Cascade Chamber of Commerce
- Donnelly Chamber of Commerce
- City of McCall
- Roseberry General Store and Museum
- Yellow Pine Backcountry Historical Museum Back Country History Project Yellow Pine Times Yellow Pine Harmonica Contest
- Warm Lake Users Assoc.