Zelienople, PA was founded in 1802 by Dettmar Basse, who came to America from Germany. He Bought 10,000 acres of Depreciation Lands and established a town, which he named Zelienople for his eldest daughter Zelie. In 1840, Zelienople was chartered as a borough. Today the population has grown to around 4,000 people. The Zelienople Historical Society was incorporated in 1975 to preserve and share the history of Zelienople, PA. The Society operates the two oldest homes and museums in Zelienople, the 1808-1810 Passavant House and the 1819 Buhl House, as historic house museums.