Tract-Level ACS Data by Urban Area

In the sidebar of the map below, you can select one of the U.S.'s 20 biggest urban areas (as of the 2010 census) and a variable from the 2019 American Community Survey (ACS) to display a tract-level breakdown of that variable for each tract in the urban area. The color scale runs from red (lowest) to blue (highest) regardless of variable, with white as the color of the average for the full urban area. Each tract's exact number, the urban area's average, and each tract's population and housing stock (in number of housing units) is displayed when you hover your cursor over the tract on the map.

The motivation behind grouping cities/metro areas by the Census-designated "urban area", as opposed to city or metropolitan statistical area (MSA), is to isolate the metro area's housing market. The Census Bureau designates urban areas after each decennial census to delineate urban populations around some core commercial center without relying on legal/administrative boundaries such as state, city, or county lines. This designation is more reflective of where new or existing residents of a metro area will move or live than city boundaries (which under-cover the metro area) or MSA boundaries (which over-cover by relying on county lines). Tract-level breakdowns of Census data tend to rely on MSAs because tracts nest within counties, whereas urban areas are built using Census blocks, which are the lowest geographic designation. Only decennial Census data is released by block, whereas the ACS releases data by tract.The maps above are obtained by subsetting each MSA's census tract by those which overlap with its urban area. For comments, questions, or feedback on this work, please email me at edgel@wisc.edu.