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.

Westmoreland County is a county in the Commonwealth of Pennsylvania, United States, located in the Pittsburgh Metropolitan Statistical Area. As of the 2020 census, the population was 354,663. The county seat is Greensburg and the most populous community is Hempfield Township. It is named after Westmorland, a historic county of England. The county is part of the Southwest Pennsylvania region of the state.