Resident Population in Guernsey County, OH was 38.08900 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Guernsey County, OH reached a record high of 42.02400 in January of 1980 and a record low of 37.66500 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Guernsey County, OH - last updated from the United States Federal Reserve on May of 2024.