Identify Centroid Coordinate for Census Block Group

Hi, I’m working on a project requiring identifying lat/long for the centroids of census block group for all states in united states. I’m wondering if you have such mapping in the database and I can leverage? If not, I would also appreciate some guidance on how I should proceed to calculate that value from other intermediate data files?


The Census Bureau provides population-weighted centroids for block groups (along with other common geographic units) after each decennial census is conducted. We convert those files into shapefiles and disseminate them via the NHGIS Data Finder. We have population weighted centroids for 2000, 2010, and 2020.

To find those shapefiles, you need to:

  1. Go to the NHGIS Data Finder
  2. Open the Geogrpahic Levels filter popup and click the plus icon next to Block Group (by State – County – Census Tract)
  3. Next, open the Years filter and click the checkbox next to 2020
  4. Click the GIS Files tab in the Select Data grid
  5. Look at the list of shapefiles to find the one labeled Block Group (Centers of Population). When you find it, click on the green plus icon to add it to your cart.
  6. Re-do steps 3-5 for 2010 and 2020

This will provide you with point shapefiles for all three decades.

We strongly recommend using the population-weighted centroids! My colleague, Jonathan Schroeder, put together a blog post detailing why centers of population are so powerful. Jonathan also gave a talk at NACIS in 2022 showing why centers of population are more useful than geographic centroids.

Dave Van Riper

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Note: The files that Dave pointed you to are “shapefiles,” which many software packages have the ability to read. I wanted to add that if you specifically need longitude/latitude coordinates, the shapefiles provide those coordinates in their attribute tables. Alternatively, you could get the same coordinates in CSV files through this Census Bureau web page (which was the source for our files). The drop-down menus there makes it look like the block group files are only available by state, but there is a nationwide file farther down in the list, labeled “United States.”

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