Tenafly 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 15,409, an increase of 921 (+6.4%) from the 2010 census count of 14,488, which in turn reflected an increase of 682 (+4.9%) from the 13,806 counted in the 2000 census. Tenafly is a suburb of New York City.