A census block group is a geographical unit used by the United States Census Bureau

United States Census Bureau

The United States Census Bureau is the government agency that is responsible for the United States Census. It also gathers other national demographic and economic data...

 which is between the census tract

Census tract

A census tract, census area, or census district is a geographic region defined for the purpose of taking a census. Usually these coincide with the limits of cities, towns or other administrative areas and several tracts commonly exist within a county...

 and the census block

Census block

A census block is the smallest geographic unit used by the United States Census Bureau for tabulation of 100-percent data . Several blocks make up block groups, which again make up census tracts. There are on average about 39 blocks per block group, but there are variations...

. It is the smallest geographical unit for which the bureau publishes sample data, i.e data which is only collected from a fraction of all households.

Census block groups are identified by a number, usually single digit. This number determines the first digit of all the census blocks which compose the block group, for instance census block 2 would have any block numbered 2000 to 2999.

The United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 including Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

has 211,267 block groups, each containing an average of 39 blocks.

External links

• gCensus: Browse Block Groups and Block Numbers. You can also view this information using Google maps.