It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998.

Its administrative seat is the town of Czarnków, which lies 61 kilometres (38 mi) north-west of the regional capital Poznań.

The county contains three other towns: Trzcianka, 18 km (11 mi) north of Czarnków, Krzyż Wielkopolski, 38 km (24 mi) west of Czarnków, and Wieleń, 27 km (17 mi) west of Czarnków.

The county covers an area of 1,808.19 square kilometres (698.1 sq mi).

The county is subdivided into eight gminas (one urban, three urban-rural and four rural).