The total value of farmsand rural real estate for sale in Honolulu County, Hawaii, recently on Land.com was nearly $132 million. This represents nearly 100,000 acres of land and rural real estate for sale in Honolulu County. 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 Pineapple State. Honolulu had the most land for sale. Honolulu County is one of the ten biggest 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.