Stara Gradiška is a village and a municipality in Slavonia, in the Brod-Posavina County of Croatia. It is located on the left bank of the river …Stara Gradiška is a village and a municipality in Slavonia, in the Brod-Posavina County of Croatia. It is located on the left bank of the river Sava, across from Gradiška in Bosnia and Herzegovina. The first word in the name means Old as there's also a New Gradiška nearby, the town of Nova Gradiška.