Nidzica County is a unit of territorial administration and local government in Warmian-Masurian Voivodeship, northern Poland. It came into being on 1 January 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and only town is Nidzica, which lies 48 kilometres south of the regional capital Olsztyn. The county covers an area of 960.7 square kilometres.