Carlisle is a borough located in the state of Pennsylvania within the United States. It serves as the county seat for Cumberland County and is situated in the Cumberland Valley, which is recognized as a highly productive agricultural region.
The borough functions as the smaller principal city of the Harrisburg–Carlisle metropolitan statistical area, which encompasses Cumberland, Dauphin, and Perry counties in South Central Pennsylvania. As of the 2020 census, the population of the borough was 20,118, while the broader Carlisle urban cluster, including neighboring townships, had a population of 37,695.