Zelienople ( /ˌziːliənoʊpəl/) is a borough in Butler County, Pennsylvania, 28 miles (45 km) north of Pittsburgh. The population was 4,123 at the 2000 census.
According to the United States Census Bureau, the borough has a total area of 2.2 square miles (5.7 km2), of which 98% is land and 1.35% is water.
Zelienople is situated on the left bank of the Connoquenessing Creek, in an area that is rich with coal and iron ore. The elevation is 935 feet (285 m) above sea level.