Garden Valley is an unincorporated census-designated place in Boise County, Idaho, United States. As of the 2010 census, its population was 394. The mountain setting and recreation opportunities attract visitors from the Boise area. The life here in early American history, however, was harsh. Economic opportunity was based on logging, mining, and ranching. In later years there was work here as hunting guides.
Outsider artist James Charles Castle was a native of Garden Valley.