Lackawanna is a city in Erie County, New York, United States, just south of the city of Buffalo in western New York State. The population was 19,949 at the 2020 census. It is one of the fastest growing cities in New York, growing in population by 10% from 2010 to 2020. It is part of the Buffalo-Niagara Falls metropolitan area. The city of Lackawanna is in the southwestern part of Erie County.
The town's name derives from the Lackawanna Steel Company. During the early 20th century, the Lackawanna steel plant was the largest in the world.