Fair Lawn is a borough in Bergen County, in the U.S. state of New Jersey, and a bedroom suburb located 12 miles northwest of New York City. As of the 2020 United States census, the borough's population was 34,927, an increase of 2,470 from the 2010 census count of 32,457, which in turn reflected an increase of 820 from the 31,637 counted in the 2000 census.