Oaklyn is a borough in Camden County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 3,930, a decrease of 108 from the 2010 census count of 4,038, which in turn reflected a decline of 150 from the 4,188 counted in the 2000 census. The borough had the 28th-highest property tax rate in New Jersey, with an equalized rate of 4.134% in 2020, compared to 3.470% in the county as a whole and a statewide average of 2.279%.