There was a total of around $75 million of farms and rural land for sale in Coos County recently on Land.com. The total of all Coos County farms and rural real estate for sale was 4,000 acres. Coos County ranks fourth in the Granite State based on the total amount of acres of land for sale among all the counties in the Granite State. Lancaster featured the most land for sale. Coos County is the largest county in New Hampshire (1,830 square miles). It's located in the North New Hampshire region of New Hampshire.