Population Estimate, Total, Hispanic or Latino (5-year estimate) in Mercer County, IL was 514.00000 Persons in January of 2023, according to the United States Federal Reserve. Historically, Population Estimate, Total, Hispanic or Latino (5-year estimate) in Mercer County, IL reached a record high of 514.00000 in January of 2023 and a record low of 255.00000 in January of 2010. Trading Economics provides the current actual value, an historical data chart and related indicators for Population Estimate, Total, Hispanic or Latino (5-year estimate) in Mercer County, IL - last updated from the United States Federal Reserve on September of 2025.