West Mifflin is a borough located in Allegheny County, Pennsylvania, in the United States. Situated southeast of Pittsburgh, it serves as a residential community within the state's metropolitan region.
The borough was named in honor of Thomas Mifflin, who served as the first governor of Pennsylvania and was a U.S. Founding Father. According to the 2020 census, West Mifflin had a population of 19,589 residents.