Atco is an unincorporated community and census-designated place in Waterford Township in Camden County, in the U.S. state of New Jersey. It is part of the Philadelphia-Camden metropolitan area, located 16 miles southeast of Camden. Though generally considered part of Waterford Township, a small section of the southern edge of Atco is located in Winslow Township. Atco was first listed as a CDP prior to the 2020 census with a population of 9,058.