Osiek, Gmina Joniec

Osiek is a village in the administrative district of Gmina Joniec, within Płońsk County, Masovian Voivodeship, in east-central Poland. It lies approximately 3 km west of Joniec, 12 km east of Płońsk, and 53 km north-west of Warsaw.

This gentry village ("wieś szlachecka", i.e., owned by a noble) became part of the Zakroczymska land in the second half of the XVI. Between 1975 and 1998, this place belonged to the Ciechanów Voivodeship.