What is a block group?

A Census block group is a US Census statistical designation. Block groups are smaller divisions of Census tracts. They consist of groupings comprised of individual census blocks and include populations of around 600-3,000 people. Block groups are one of the smallest geographic levels for which the American Community Survey data is released. 

Learn more about block groups at: https://www.census.gov/geographies/reference-maps/2020/geo/2020-census-block-maps.html