Creating historical Congressional maps with USABoundaries

rOpenSci package or resource used


What did you do?

While reading a book about a futile presidential candidacy in the 1800s by Mormon leader Joseph Smith, I noticed that he proposed radically reshaping congressional apportionment rules and only assigning one House Representative per 1 million residents per state. I wanted to see what that would have done to Congress in the 1840s, and I wanted to make a map showing how many representatives each state would get under the proposed rules.

Finding historical GIS data is hard, but I remembered that I had starred USAboundaries on GitHub a while ago, so I tracked it down and found it incredibly easy to get a shapefile for historical US maps. All you have to do is feed the us_states() function a date, and you get the corresponding borders as an sf-ready shapefile.

URL or code snippet for your use case

You can find the full code at this gist (I use USAboundaries atarting at line 104), and I posted the finished maps and some more context in this Twitter thread.




Field(s) of application

history, political science

Twitter handle