The most accurate house price index available from the U.S. government is the FHFA House Price Index (“HPI”). The FHFA HPI offers free data on single-family homes in all 50 states from as far back as the mid-1970s.
The most accurate nongovernment-maintained house price indices are the S&P CoreLogic Case-Shiller Home Price Indices, which include up-to-date measures of U.S. residential home prices and home value changes over time.