Płońsk County is a unit of territorial administration and local government (powiat) in Masovian Voivodeship, east-central 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 largest town is Płońsk, which lies 63 km north-west of Warsaw. The only other town in the county is Raciąż, lying 25 km north-west of Płońsk. The county covers an area of 1383.67 km2. As of 2019, its total population is 87,183, out of which the population of Płońsk is 22,130, that of Raciąż is 4,384, and the rural population is 60,669.

Neighbouring counties

Płońsk County is bordered by Mława County and Ciechanów County to the north, Pułtusk County to the east, Nowy Dwór County to the south-east, Sochaczew County to the south, Płock County and Sierpc County to the west, and Żuromin County to the north-west.

Administrative division

The county is subdivided into 12 gminas (two urban and 10 rural). These are listed in the following table, in descending order of population.