Ada County is in Southwestern Idaho. Of the 44 counties in the Gem State, Ada County ranks 31st in terms of size (1,060 square miles). Recent listings of residential land for sale in Idaho's Ada County totals roughly 1,000 acres and a combined market value of approximately $530 million. The most common type of land for sale by combined acreage in Ada County is residential property. The average price of residential land for sale in Ada County was $2 million. Browse all residential land and rural property for sale in Idaho to find residential land and properties that suit your lifestyle needs, from existing residential homes and estates to land ready for future residential-property development.