Sewickley is a borough in Allegheny County, Pennsylvania, 12 miles (19 km) west northwest of Pittsburgh along the Ohio River. It is a residential suburb of Pittsburgh. The population was 3,827 at the 2010 census. The Sewickley Bridge crosses the Ohio River at Sewickley.
Sewickley is thought to be a Native American word meaning "sweet water." Historians dispute if Native Americans were referring to the Ohio River as the "sweet water" or instead to the syrup derived from a local abundance of maple trees.
According to the United States Census Bureau, the borough has a total area of 1.1 square miles (2.8 km2), of which, 1.0 square miles (2.5 km2) of it is land and 0.1 square miles (0.3 km2) of it (11.11%) is water.