Lubnia is a village in the administrative district of Gmina Brusy, within Chojnice County, Pomeranian Voivodeship, in northern Poland. It lies approximately 6 km north of Brusy, 29 km north-east of Chojnice, and 76 km south-west of the regional capital Gdańsk. It is located within the historic region of Pomerania. Lubnia was a royal village of the Polish Crown, administratively located in the Tuchola County in the Pomeranian Voivodeship.