Resident Population in Union County, PA was 42.04200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Union County, PA reached a record high of 45.57300 in January of 2015 and a record low of 28.60300 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Union County, PA - last updated from the United States Federal Reserve on May of 2024.