Kościerzyna is a town located in the Kashubia region of northern Poland, within the Pomeranian Voivodeship. As of June 2023, the municipality has a population of 23,327 inhabitants.
The town serves as the capital of Kościerzyna County. It held this administrative status starting in 1999, having previously served as a seat within the Gdańsk Voivodeship from 1975 to 1998.