Masovian Voivodeship (Polish: województwo mazowieckie, pronounced [vɔjɛˈvut͡stfɔ mazɔˈvjɛt͡skʲɛ] ) is a voivodeship (province) in east-central Poland, containing Poland's capital Warsaw.
Masovian Voivodeship has an area of 35,579 square kilometres (13,737 sq mi) and had a 2019 population of 5,411,446, making it Poland's largest and most populous province. Its principal cities are Warsaw (1.783 million) in the center of the Warsaw metropolitan area, Radom (212,230) to the south, Płock (119,709) to the west, Siedlce (77,990) to the east, and Ostrołęka (52,071) to the north. It borders six other provinces: Warmian-Masurian to the north, Podlaskie to the northeast, Lublin to the southeast, Świętokrzyskie (Holy Cross) to the south, Łódź to the southwest, and Kuyavian–Pomeranian to the northwest.