Output port that contains a United States census block number.
The Census Bureau uses census tracts and census blocks to organize census data. A census tract is composed of census block groups. A census block group is composed of census blocks.
The Census Bureau uses demographic data to define census tracts, so that the inhabitants of each tract have a common economic status and population profile. The Census Bureau does not use demographic data to define census blocks.
A census block group contains an average of 39 census block. Each census block group has a maximum of 3,000 inhabitants. A census tract can contain between one and nine census block groups.
In a city, a census block may correspond to a city block. In rural areas, the Census Bureau may use a physical feature, such as a river, to define a census block boundary.
Census block populations vary greatly. A quarter of all census blocks have no inhabitants.
Census Block Number Usage
Select Census Block Number to identify the census block that an address belongs to.
Use census tract and census block data to analyze the distribution of your mail items. For example, before you run a direct mail campaign, you can use census tract and census block data to verify that mail items are distributed evenly across a city or region.
Port Location
The following table provides the location and default precision of the Census Block Number port:
Port Type
Port Group
Template Model
Precision
Output
US Supplementary
Basic
4
Census Block Number Output Codes
Census block numbers are unique within a census tract. Most census block numbers have three digits.
A census block number may add a letter to the block number if the block area crosses another geographical boundary, such as a minor civil division boundary.
The Census Bureau maintains a Geographic Areas Reference Manual that describes census blocks and other population areas. You can read the manual on the following site: