Valley County is a county located in the west central part of the U.S. state of Idaho. The county was established in 1917, named after the Long Valley of the North Fork of the Payette River, which extends nearly 30 miles from Payette Lake at McCall south to Cascade. The valley was formerly a summer pasture for Boise Valley livestock. Since the construction of the Cascade Dam in 1948, much of the valley has been covered by the Cascade Reservoir (Lake Cascade). As of the 2000 Census, the county had a population of 7,651 (2005 estimate: 8,332) The county seat is Cascade.
Valley County is home to the Idaho ground squirrel.
There were 3208 households out of which 28.10% had children under the age of 18 living with them, 60.90% were married couples living together, 5.40% had a female householder with no husband present, and 29.80% were non-families. 24.80% of all households were made up of individuals and 7.90% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.81.
In the county the population was spread out with 23.70% under the age of 18, 4.40% from 18 to 24, 24.90% from 25 to 44, 32.20% from 45 to 64, and 14.80% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 105.90 males. For every 100 females age 18 and over, there were 104.40 males.
The median income for a household in the county was $36,927, and the median income for a family was $42,283. Males had a median income of $31,113 versus $21,777 for females. The per capita income for the county was $19,246. About 6.20% of families and 9.30% of the population were below the poverty line, including 10.10% of those under age 18 and 5.60% of those age 65 or over.