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.

The following table provides the location and default precision of the Census Block Number port:

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: