There are also three Donegal Townships in Pennsylvania. Donegal is a borough in Westmoreland County, Pennsylvania, United States. It is a distinct municipality from the adjacent Donegal Township. The population was 103 at the 2020 census. Donegal is best known as an exit on the Pennsylvania Turnpike with restaurants, gas stations, and two hotels for travelers. It was named after the town and county of Donegal in Ireland.