Obkas-Młyn [ˈɔpkas ˈmwɨn] is a village in the administrative district of Gmina Kamień Krajeński, within Sępólno County, Kuyavian-Pomeranian Voivodeship, in north-central Poland. It lies approximately 3 kilometres (2 mi) north of Kamień Krajeński, 12 km (7 mi) north of Sępólno Krajeńskie, and 59 km (37 mi) north-west of Bydgoszcz.