Percentage of slaves in the US over time, 1790-1860.
Data source: US Census data hosted by NHGIS.org, the National History GIS project at the University of Minnesota.
NHGIS is a great resource for historical GIS research on the US, and I can’t recommend it highly enough.
I’d just like to bring your attention to #Maine.
142 notes (via howlind & mapsontheweb)