This data was created by combining the 2010 Census Block Group file as well as the Legal City Boundaries maintained by the LA County Department of Public Works.

In reviewing this overlap, LA County aligned a fairly large number of block group boundaries to city boundaries where those boundaries were identified as being incorrectly misaligned by the Census Bureau. This removed split block groups that did not have any population assigned to them.

To support the development of the Countywide Statistical Areas, , some split block groups that had multiple parts were “unmerged” so that non-contiguous portions of the split block group could be assigned to different CSAs. Examples include areas of Unincorporated Quartz Hill and Lancaster that have 2 or more CSA names for a single split block group. Those portions are identified as “Parts” and tracked in the “Parts” field.

In the City of Los Angeles, the LA City Neighborhood file was overlaid on the Block Groups and boundaries assigned using the centroid of the block group therefore, while the names of the CSAs in LA City match the neighborhood file, the boundaries are not the same.

Field Descriptions:

• BG10 2010 Block Group (7 digits)

• CT10 2010 Census Tract (6 digits)

• FIPxx 2010-2020 City Code (5 digit FIPS code - note that Unincorporated is 99037)

• CITY_TYPE "City" or "Unincorporated"

• LCITY Legal City Name

• CSA - Countywide Statistical Area Name (e.g. Community)

• LABEL Pretty name for Labelling

• SOURCE CSA source

• BG10FIPxx 2010 - 2020 Split Block Group (Block group and FIP code combined)

• CT10FIPxx 2010 - 2020 Split Tract (Tract and FIP code combined)

• DISTRICT 2011 Supervisorial District

• NOTES Notes relevant to the geography

• PART Part number (for non-contiguous split block groups)

• PARTS Total number of non-contiguous parts (for non-contiguous split block groups)

• CSA_ID Unique BASA ID - combination of 2016 Split Block Group and Part Number

• MERGED Flag if the Split BLock Group was merged into multi-part shapes

• CITYCOMM - merged values for the legal city, community, and supervisorial district

• REMARKS - additional remarks about the source of any changes.