Portersville, IndianaPortersville is an unincorporated community in [Boone Township, Dubois County, Indiana|Dubois County, Indiana|Boone Township], Dubois County, in the U.S. state of Indiana.HistoryPortersville was established as a town circa 1818. It is reportedly the oldest town in Dubois County, and was selected as the county seat of Dubois County before it was changed to Jasper. A post office was established at Portersville in 1821, and remained in operation until it was discontinued in 1909.