Population Estimate, Total, Not Hispanic or Latino, White Alone (5-year estimate) in Mercer County, IL was 14606.00000 Persons in January of 2023, according to the United States Federal Reserve. Historically, Population Estimate, Total, Not Hispanic or Latino, White Alone (5-year estimate) in Mercer County, IL reached a record high of 16071.00000 in January of 2010 and a record low of 14606.00000 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Population Estimate, Total, Not Hispanic or Latino, White Alone (5-year estimate) in Mercer County, IL - last updated from the United States Federal Reserve on September of 2025.