New Castle is a city located in Lawrence County, Pennsylvania, in the United States. It serves as the county seat and is situated along the Shenango River at the mouth of Neshannock Creek. The city sits approximately 43 miles northwest of Pittsburgh near the Pennsylvania–Ohio border and about 17 miles southeast of Youngstown, Ohio.
The city functions as the commercial center of a fertile agricultural region and is positioned within the northwestern fringes of the Pittsburgh metropolitan area. As of the 2020 census, New Castle had a population of 21,926.