Land for sale in Honolulu County recently totaled almost $691 million and around 3 million acres. Based on the combined acreage of land and rural property for sale here, Honolulu County has the most land for sale of all counties in the Aloha State. Among cities in Honolulu County with farms and rural real estate for sale, Honolulu featured the most land for sale. Honolulu County is one of the ten largest counties in Hawaii (2,166 square miles, or some 100 percent of the state's total land area). It's located in the Oahu Hawaii region of the state.