Resident Population in Lancaster County, PA was 558.58900 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Lancaster County, PA reached a record high of 558.58900 in January of 2023 and a record low of 320.07900 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Lancaster County, PA - last updated from the United States Federal Reserve on May of 2024.