New Castle is a city in Lawrence County, Pennsylvania, 50 miles (80 km) northwest of Pittsburgh, Pennsylvania an 18 miles (30 km) east of Youngstown, Ohio; in 1910, the total population was 36,280; in 1920, 44,938; and in 1940, 47,638. The population was 26,309 at the 2000 census. It is the county seat of Lawrence County. New Castle is part of the Pittsburgh metropolitan area and the Pittsburgh-New Castle combined statistical area. It is the commercial centre of a fertile agricultural region. New Castle is a prime example of a Rust Belt city which has been forced to adapt to changing economic situations.