Borsk is a village in the administrative district of Gmina Karsin, within Kościerzyna County, Pomeranian Voivodeship, in northern Poland. It lies approximately 6 km north of Karsin, 19 km south of Kościerzyna, and 66 km south-west of the regional capital Gdańsk. It is located within the ethnocultural region of Kashubia in the historic region of Pomerania. Borsk was a royal village of the Polish Crown, administratively located in the Tuchola County in the Pomeranian Voivodeship.