Lyndhurst is a township in Bergen County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 22,519, an increase of 1,965 (+9.6%) from the 2010 census count of 20,554, which in turn reflected an increase of 1,171 (+6.0%) from the 19,383 counted in the 2000 census.