Of 21 counties in the state, Middlesex County ranks 13th in terms of size (322 square miles). Middlesex County is in North New Jersey. Middlesex County, New Jersey, includes almost 1,000 acres of farms for sale based on recent Land Network data. The combined market value of land and rural real estate for sale here was roughly $2 million. Browse all Middlesex 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 Middlesex County is house.