All-Transactions House Price Index for Williamson County, IL was 179.91000 Index 2000=100 in January of 2023, according to the United States Federal Reserve. Historically, All-Transactions House Price Index for Williamson County, IL reached a record high of 179.91000 in January of 2023 and a record low of 60.87000 in January of 1979. Trading Economics provides the current actual value, an historical data chart and related indicators for All-Transactions House Price Index for Williamson County, IL - last updated from the United States Federal Reserve on May of 2024.