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How is a census block determined?
In a city, a census block looks like a city block bounded on all sides by streets. Numbered uniquely with a four-digit census block number ranging from 0000 to 9999 nesting within each census tract, which nest within state and county. The first digit of the census block number identifies the block group.
When were census blocks created?
1940
In 1940, the Census Bureau also began publishing census block data for all cities with 50,000 or more inhabitants. Census block numbers were assigned, where possible, by census tract, but for those cities that had not yet delineated census tracts, ”block areas” were created to assign census block numbers.
How are census blocks numbered in the US?
Census blocks are numbered uniquely with a four-digit census block number from 0000 to 9999 within census tract which nest within state and county. The first digit of the census block number identifies the block group. Block numbers beginning with a zero (in Block Group 0) are only associated with water-only areas.
How are census blocks used in legislative redistricting?
BAFs are among the geographic products provided to states and other data users containing the small area census data necessary for legislative redistricting. 2010 Census Block Relationship files are provided as a tool to help data users compare the universe of Census 2000 blocks to the universe of 2010 Census blocks.
What happens when a census block is split?
They may be split when a change in another geographic boundary occurs, such as an incorporated place annexation. If a block is split in between decades, a suffix will be added to the block number. For example, block 1000 would become block 1000A and 1000B.
How does the Census Bureau determine the boundaries of a reservation?
The Census Bureau contacts representatives of American Indian tribal governments to identify the boundaries for federal reservations through its annual Boundary and Annexation Survey. Federal reservations may cross state and all other area boundaries.