Niedarzyn [ɲɛˈdaʐɨn] is a village in the administrative district of Gmina Baboszewo, within Płońsk County, Masovian Voivodeship, in east-central Poland. It lies approximately 6 kilometres (4 mi) north of Baboszewo, 16 km (10 mi) north-west of Płońsk, and 78 km (48 mi) north-west of Warsaw.