A BG usually covers a contiguous area. Each census tract contains at least one BG, and BGs are uniquely numbered within the census tract. Within the standard census geography hierarchy, BGs never cross state, county, or census tract boundaries but may cross the boundaries of any other geographic entity.

There are little more number of Census Block Groups within Los Angeles County in 2020 Census TIGER/Line Shapefiles, compared in 2010.

UPDATED:

1. September 2023: Previous census block group data for Long Beach breakwater was broken into different silver polygons for land-based tracts. These silvers were merged into bigger block group 9903000 based on 2022 TIGER Line Shapefile. In addition, Santa Catalina Island and San Clemente Island block group boundary were updated based on DWP City boundary and CSA boundary (except CT 5990002 in Avalon).

2. December 2022: Aligned census block group boundary with updated city boundary along shoreline/coastal areas, from Malibu to Long Beach. This data also includes Long Beach City water area block group 9903000.

3. September 2022: Previous dataset from March 2021 was clipped to County boundary. New dataset retains shoreline census geography in their entirety.

CREATED: March 2021

How This Data is Created?

This geographic file was downloaded from Census Bureau website: https://www2.census.gov/geo/tiger/TIGER2020PL/STATE/06_CALIFORNIA/06037/ on February, 2021 and customized for LA County.

Data Fields:

1. BG20 (BLKGRPCE20): 7 digit census tracts and block group number

2. CT20 (TRACTCE20): 6-digit census tract number

3. Label (NAMELSAD20): Block group number label

Note:

If you are interested to check original block group 2020 boundary, review the census block 2020 data (BG20 field).