Can you provide data for geographies smaller than zip codes?
Yes, you can get data for Census tracts, block groups and blocks – all of which tend to be smaller than zip codes.
- Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people. The most current Census data are available for Census tracts. For most projects, we recommend using Census tracts, because they tend to have lower margins of error than do block groups.
- Block groups are generally defined to contain between 600 and 3,000 people. Block groups are the smallest geographic for which the most current Census data are available.
- Census blocks are typically bounded by streets, roads, or creeks. In cities, a census block may correspond to a city block, but in rural areas where there are fewer roads, blocks may be delineated by other features. The population of a census block varies greatly. Blocks are the smallest geographic area for which Census data are available, and are only available from the Decennial Census (e.g. Census 2010). The only data published at this level are basic demographics like population by age, race, sex and household type. Income data are not available for blocks. A full list of subjects from the most recent Census can be found at https://www.census.gov/prod/cen2010/doc/sf1.pdf.