In early 1807 in Ostrołęka the battle of Napoleon's campaign between French and Russian armies took place, won by Napoleon armies. The fact that name of the city was gullied on Triumphal Arc in Paris, speaks for it's importace.
The most dynamic development of city was in XX century. Ostrołęka, although lies among agricultural lands, is important industrial centre. Cellulose-paper factory and the group of power stations were built. 30% of cellulose and packagings from wavy cardboard produced in the Poland comes from here.
Ostrołęka lies on the cross of roads from center and south of Poland on northern-ascent. From south it adjoins with the area of Warsaw agglomeration, creating it's natural reserve. National road 61( also called "gościniec mazurski") runs thru the city, leading from Warsaw to most beautiful Polish lakes. City has direct road connection with Warsaw, Olsztyn and Białystok, the greatest cities of north – east Poland. Traveling distance to each of the above cities is about 120 km.
Educational base of the city is very well developed – there are several primary and secondary schools, with good athletic subsidiaries. The city's Sports and Recreation Centre is responsible for organization of sport life in the city. There are number of sport facilities in the city like: concert-athletic hall, roofed swimming pool, tennis grounds, and a stadium with 2500 seats. Leading athletic disciplines, in which local clubs are successful are: volleyball, football, popular dance.
The local Center of Culture conducts many interesting projects including promotion of local tradition.
Every year in May (12 – 26 May) an event called "Days of Ostrołęka" takes place. It's organized by The City Council and includes garden parties, athletic competitions, musical concerts. Important part of the event is an open air show "Battle under Ostrołęka", commemorating the events of May 1831 (important battle of national revolt directed against Russians invading Poland).
The city has about 53 thousand residents.
Bridge built in 1995 in form of an arc, modeled on bridge in Sewilla is the most recognizable symbol of city.