If you visit the U.S. Census Bureau looking for the latest housing data, you might be surprised to find that the most recent release covers data ending a year or two ago. In 2026, the newest county-level data is the 2020–2024 ACS 5-Year Estimates, released in January 2026.

Why the lag? And why does it matter for anyone trying to understand the housing market?

What Is the American Community Survey?

The ACS is the largest household survey in the United States, conducted continuously by the U.S. Census Bureau. It samples roughly 3.5 million addresses per year and asks detailed questions about income, education, housing, employment, and more.

Unlike the decennial Census (which counts everyone every 10 years), the ACS provides continuous, ongoing data. But that continuity comes with a statistical trade-off.

1-Year vs. 5-Year Estimates

The ACS publishes two main types of estimates:

  • 1-Year Estimates: Released annually, based on 12 months of survey responses. Only available for areas with populations of 65,000+.
  • 5-Year Estimates: Released annually, based on 60 months of survey responses. Available for all geographies, including small counties and census tracts.

For county-level data covering all 3,143 U.S. counties, the 5-Year Estimates are the only option. The 1-Year Estimates simply don't have enough sample size for small counties.

Why 5-Year Estimates Lag

The 5-Year Estimates use data collected over a 5-year window. To publish the 2020–2024 estimates, the Census Bureau needs:

  1. All survey responses from January 2020 through December 2024
  2. Time to weight and adjust the data for non-response bias
  3. Time to run statistical models and quality checks
  4. Time for peer review and final validation

This process takes roughly 12 months after the survey period ends. So 2020–2024 data becomes available in January 2026.

What This Means for Housing Data

When you see a '2024' median home value on our site, it represents an average over 2020–2024, not a snapshot of December 2024. This has several implications:

  • Smoothed trends: Short-term volatility (like the 2021 boom) is averaged out, which is good for identifying structural trends but bad for spotting turning points.
  • Historical perspective: The 5-year window is long enough to reflect real market shifts, but short enough to stay relevant.
  • Consistency: Every county, no matter how small, uses the same methodology—making cross-county comparisons reliable.

Comparing Public and Private Data Sources

Alternative data sources exist—such as Zillow ZHVI, Redfin, and FHFA HPI, which update monthly or quarterly. Each serves a distinct purpose:

  • Zillow ZHVI: Monthly metric tracking estimated market values, highly useful for near-term momentum.
  • Redfin: Provides rapid MLS-based transactional insights and market movement trends.
  • FHFA HPI: Quarterly index based on mortgage transactions bought by Fannie Mae/Freddie Mac, covering ~2,800 counties.

While private metrics offer faster real-time market signals, the Census ACS provides the most comprehensive, standardized baseline covering all 3,100+ U.S. counties. To offer the most complete picture possible, we plan to integrate additional private indicators like Zillow and Redfin in future updates alongside our core public datasets.

How to Combine ACS with Faster Data

The best approach is layered:

  1. ACS 5-Year (baseline): Understand the structural price level and long-term trends.
  2. FHFA HPI & Private Market Indices (momentum): Track recent changes and shorter-term market dynamics.
  3. FRED (rates): Track interest rates and macro context.

This layered approach gives both perspectives: 'what the market looks like structurally' and 'where it's heading recently.'

When Will 2025 Data Be Available?

The 2021–2025 ACS 5-Year Estimates are scheduled for release in December 2026. Our automation will pick them up automatically on the next data refresh after that date.

The Bottom Line

Data lag isn't a flaw—it's the cost of statistical reliability. For decisions that require a long-term view (buying a home, choosing where to live, planning investments), the 5-Year Estimates are more trustworthy than fast-moving alternatives. For recent momentum, we supplement with FHFA and will continue expanding our dataset options over time. Understanding both is the key to reading housing data correctly.