A total of almost 4,000 acres were listed for sale in Colorado's Boulder County recently, representing a total value of approximately $412 million in Boulder County farms and ranches for sale. Boulder County ranks 19th in Colorado for the combined amount of land currently advertised for sale. Of all locations in Boulder County with farms, ranches, and rural real estate for sale, Boulder had the most land for sale. Boulder County is Colorado's 51st biggest county (740 square miles). It's located in the Front Range Colorado region of the state.