Aliquippa is a city in Beaver County, Pennsylvania, United States, along the Ohio River. The population was 9,238 at the 2020 census. It is located 18 miles northwest of Pittsburgh and is part of the Pittsburgh metropolitan area. Formerly the location of a large Native American trading center, Aliquippa grew to become a center for steel manufacturing by the early 20th century, similar to other towns in the area.