Nowy Dwór Mazowiecki County
Nowy Dwór Mazowiecki County is a unit of territorial administration and local government in Masovian Voivodeship, east-central Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and largest town is Nowy Dwór Mazowiecki, which lies north-west of Warsaw. The county also contains the towns of Nasielsk, lying north-east of Nowy Dwór Mazowiecki, and Zakroczym, west of Nowy Dwór Mazowiecki. Warsaw-Modlin Airport is located within the county.
The county covers an area of. As of 2006 its total population is 75,736, out of which the population of Nowy Dwór Mazowiecki is 27,545, that of Nasielsk is 7,364, that of Zakroczym is 3,367, and the rural population is 37,460.Neighbouring counties
Nowy Dwór Mazowiecki County is bordered by Pułtusk County to the north-east, Legionowo County to the east, Warsaw West County to the south, Sochaczew County to the south-west and Płońsk County to the north-west.The county is subdivided into six gminas. These are listed in the following table, in descending order of population.
| Gmina | Type | Area
| Population
| Seat |
| Nowy Dwór Mazowiecki | urban | 28.3 | 27,545 | |
| Gmina Nasielsk | urban-rural | 202.5 | 19,259 | Nasielsk |
| Gmina Pomiechówek | rural | 102.3 | 8,820 | Brody-Parcele |
| Gmina Czosnów | rural | 128.3 | 8,743 | Czosnów |
| Gmina Zakroczym | urban-rural | 71.4 | 6,277 | Zakroczym |
| Gmina Leoncin | rural | 158.8 | 5,092 | Leoncin |
