Hunterdon County is located in the U.S. state of New Jersey. It is part of the New Jersey Metropolitan Area. Its county seat is Flemington. Hunterdon ranks 13th among the highest-income counties in the US with a per capita income of $36,370. It ranks third among U.S. counties for household income.Hunterdon County has a total area of approximately 438 square miles of which 98% is land and 2% water. As of the 2000 census, there were 121,989 people, 43,678 households, and 32,845 families residing in Hunterdon County, NJ.