Leoncin pronounced [lɛˈɔnt͡ɕin] is a village in Nowy Dwór Mazowiecki County, Masovian Voivodeship, in east-central Poland. It is the seat of the gmina (administrative district) called Gmina Leoncin.Leoncin is approximately 40 kilometres (25 mi) north-west of Warsaw. It has a neogothic church from 1885, as well as a wooden chapel dating from the end of the 18th century that is located at a nearby cemetery. It is also famous for being the birthplace of Isaac Bashevis Singer.