The value of all land for sale in Boise County recently was almost $105 million, representing a combined 3,598 acres of land for sale in Boise County. Boise County ranks 10th in the state for the total number of acres of land currently advertised for sale. Of all farms, ranches, and rural real estate for sale in Boise County, Garden Valley featured the most land for sale. Government and state-level services are the main economic drivers in Boise County. Boise County is the 15th biggest county (1,906 square miles) in Idaho. It's located in the Southwestern Idaho region of Idaho.