Land for sale in Clark County, Idaho, recently totaled nearly $28 million and 2,000 acres. Clark County ranks 43rd in the Gem State for the total number of acres of land currently advertised for sale. Dubois featured the most land for sale. Agriculture and farming drives the Clark County economy, with 72 farms recorded in the county during the U.S. Census in 2012. Farming activities in Clark County generate annual revenues of $186,000, most of which is from crops. Clark County is the 19th biggest county (1,764 square miles) in Idaho. It's located in the Eastern Idaho region of Idaho.