Karolin, is a village in the administrative district of Gmina Giby, within Sejny County, Podlaskie Voivodeship, in north-eastern Poland, close to the borders with Belarus and Lithuania. It lies approximately 6 kilometres (4 mi) west of Giby, 10 km (6 mi) south-west of Sejny, and 104 km (65 mi) north of the regional capital Białystok.