Sisak is a city located in central Croatia. It is situated at the confluence of the Kupa, Sava, and Odra rivers, approximately 57 km (35 mi) southeast of the Croatian capital, Zagreb. The city sits at an elevation of 99 meters and is generally considered to be the starting point of the Posavina region.
As of 2021, the total population of Sisak was 40,185. Of this population, 27,886 residents live within the urban settlement (naselje).