New Milford is a borough in Bergen County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 16,923, an increase of 582 (+3.6%) from the 2010 census count of 16,341, which in turn reflected a decline of 59 (−0.4%) from the 16,400 counted in the 2000 census.