Of 10 counties in the state, Merrimack County ranks fourth in terms of size (954 square miles). Merrimack County is in Central New Hampshire. Merrimack County, New Hampshire, has nearly 1,000 acres of farms for sale based on recent Land Network data. The combined market value of farmsand rural real estate for sale here was about $3 million. Browse all Merrimack County farms for sale on the Land Network to find the farm, cattle operation, hobby farm or other farm property that's right for your future business or individual needs. The most common type of land for sale by combined acreage in Merrimack County is residential property.