Ostrołęka is a small city located in northeastern Poland on the Narew river. It is situated approximately 120 km (75 mi) northeast of the capital city, Warsaw.
The city serves as the administrative capital for both Ostrołęka County and Ostrołęka City County within the Masovian Voivodeship. As of 2021, it has a population of 51,012 and covers an area of 33.46 square kilometres (12.92 sq mi).