ACS Data Users Group

Hello colleagues, I'm looking for a list of geographic variant codes. These are found in the 4th and 5th digits of the standard census geoid.

I'm not sure whether ACS actually uses these (other than "00"), but they are fairly common in the new DHC data. The DHC documentation only says that geographic variant code "Indicates the version of a geographic entity, based on the date of the entity’s boundaries." Not helpful without a key.

From context, I can surmise that variant "C2" refers to urban/rural designation, since C2 geographies always have geographic components of 01 (urban) or 43 (rural). Other variant codes include 16, L6, M6, U6, and Z2. There may be others I'm not aware of.

Thanks!

Dear Glenn,

Is this what you are looking for?

www.census.gov/.../class-codes.html

Thanks David, but I think this is different. For instance, the list you posted doesn't include M6. I'm not really concerned though, mostly just curious.

I don't have a definitive list, however through some sleuthing I was able to figure out:

• 16 refers to the congressional district version
• L6 refers to the state legislative district (lower chamber) version
• U6 refers to the state legislative district (upper chamber) version
• M6 refers to the metropolitan statistical area/micropolitan statistical area version
• Z2 refers to the of zip code tabulation area version

Unfortunately, I don't have much more information on when the variants changed, however you can visually check by querying the ACS API where you include GEO_ID and change vintages.

Good morning! I wanted to mention that our geography area has now posted a list of the geographic variant codes and definitions at https://www.census.gov/programs-surveys/geography/guidance/geo-variants.html.