(April 2009) The ACS data are tabulated for a variety of different geographic areas ranging in size from broad geographic regions (Northeast, Midwest, South, and West) to neighborhoods and clusters of city blocks. One-year estimates are currently available for geographic areas with at least 65,000 people, including regions, divisions, states, DC, Puerto Rico, Congressional districts, Public Use Microdata Areas, and many large counties, metropolitan areas, cities, school districts, and American Indian areas.1 Three-year estimates are available for all areas with at least 20,000 people, and by 2010, we will have five-year estimates for geographic areas down to the block group level. This means that by 2010, there will be one-year, three-year, and five-year estimates—three sets of numbers—available for the state of Virginia, for example. But less populous areas, such as Bath County in Virginia's Shenandoah Valley, will only receive five-year estimates.

For more information about understanding and accessing data from the ACS, see:


  1. Public Use Microdata Areas, or PUMAs, are census-constructed geographic areas, each with approximately 100,000 population. PUMAs do not cross state lines.