In the first half of the 18th century, Sava-Danube (Posavina-Podunavlje) section of the Habsburg Military Frontier existed in the area. Posavina segment of the Frontier comprised parts of the Kingdom of Croatia-Slavonia – the southern parts of Slavonia and Syrmia, stretching from Nova Gradiška to the confluence of the Drina river into the Sava.
Between 1929 and 1939, one of the provinces of the Kingdom of Yugoslavia was known as the Croatian region Sava Banovina. The capital city of the province was Zagreb in Croatia. In 1939, Sava Banovina was merged with Littoral Banovina to form new Banovina of Croatia.
The Bosnian Posavina region was gravely hit by the war in Bosnia and Herzegovina (1992–95) to the point that parts of it had become uninhabited, as almost all the houses were plundered, burnt or destroyed. Only a small number of people have returned to their homes. The majority of refugees live in and around the city of Slavonski Brod, Croatia right across the Sava River, while a minority emigrated to the European Union countries, the United States, and Australia.
Cities and towns in Croatia:
Cities and towns in Bosnia and Herzegovina:
Cities and towns in Serbia: