There was a total of $341 million of farms, rural land, hunting land and other land for sale in Mercer County, New Jersey, recently on Land.com. The total size of all Mercer County farms, hunting land and other rural land and acreage for sale was around 1,000 acres. Mercer County ranks 11th out of 21 counties in the state for the total number of acres of land currently advertised for sale. Of all land and rural real estate for sale in Mercer County, Princeton featured the most land for sale. From an economic perspective, government and state-level services contribute most to Mercer County's overall GDP. Mercer County is New Jersey's 16th biggest county (228 square miles). It's located in the Central New Jersey region of the state.