The County of Newark, N.J. is located in Essex County. Essex County is a county in the northeastern part of New Jersey and is part of the New York metropolitan area. It is the third-most populous county in the state, with a population of 783, 969 in 2019. The county seat is Newark, the most populous city in the state. Essex County is home to many major cities, including Bloomfield, East Orange, Irvington, and Montclair.