Land for sale in Mississippi's Lamar County recently totaled around $102 million and nearly 3,000 acres. Lamar County ranks 10th in Mississippi for the total acreage of land currently advertised for sale. Among cities in Lamar County with farms, rural land, hunting land and other land for sale, Hattiesburg had the most land for sale. Lamar County is Mississippi's 52nd biggest county (499 square miles). It's located in the Coastal Mississippi region of Mississippi.