Fair Lawn is a borough in Bergen County, New Jersey, United States, and a suburban municipality in the New York City Metropolitan Area. As of the 2010 United States Census, the borough's population was 32,457, reflecting an increase of 820 (+2.6%) from the 31,637 counted in the 2000 Census, which had in turn increased by 1,089 (+3.6%) from the 30,548 counted in the 1990 Census.