The overall value of farmsand rural real estate for sale in Coos County, New Hampshire, recently on Land.com was around $104 million. This represents 4,000 acres of farms, hunting land and other rural land and acreage for sale in Coos County. Coos County ranks seventh based on the total acres of land for sale among the 10 counties in the Granite State. Of all land and rural real estate for sale in Coos County, Lancaster had 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 the state.