Konstancin-Jeziorna [kɔnsˈtant͡ɕin jɛˈʑɔrna] is a town in Piaseczno County, Masovian Voivodeship, Poland, with 17,566 inhabitants (as of March 2011, according to GUS). It is located about 20 km (12 mi) south of downtown Warsaw and is a part of the metropolitan area of that city. The town was created in 1969 through combining neighbouring towns: holiday resort Skolimów-Konstancin and industrial Jeziorna with a number of villages.