Ostro ka is a town in northeastern Poland on the Narew river, about 120 km (75 miles) northeast of Warsaw, with a population of 53,982 (2008) and an area of 29 km2 (11 sq. mls). Situated in the Masovian Voivodeship (since 1999), previously capital of Ostro ka Voivodeship (1975 1998). Currently capital of both Ostro ka County and Ostro ka City County. Until late 1980s, it used to be a local railroad junction, with four lines stemming from here - eastwards to apy and Bia ystok, southwestwards to T uszcz and Warsaw, northwards to Wielbark and Olsztyn, and southwards to Ma kinia.