Sienica [ɕɛˈnit͡sa] is a settlement in the administrative district of Gmina Czersk, within Chojnice County, Pomeranian Voivodeship, in northern Poland. It lies approximately 6 kilometres (4 mi) west of Czersk, 26 km (16 mi) north-east of Chojnice, and 79 km (49 mi) south-west of the regional capital Gdańsk.

For details of the history of the region, see History of Pomerania.