Moonachie is a borough in Bergen County, in the U.S. state of New Jersey, in the Hackensack River watershed. As of the 2020 United States census, the borough's population was 3,133, an increase of 425 from the 2010 census count of 2,708, which in turn reflected a decline of 46 from the 2,754 counted in the 2000 census. Tradition is that the borough was named after Monaghie, an Iroquois chief who inhabited the local cedar forests in the 1600s.