|Map by Benjamin Schmidt; click on the image to enlarge it or click here to see the interactive version|
A new interactive map shows the change in population density at the county level from 1790 to 2010. Northeastern University assistant professor Benjamin Schmidt created the map using data compiled by Jonathon Schroeder of the University of Minnesota's Minnesota Population Center. Schmidt notes that the map is flawed because it relies on census data, which did not count most Native American populations in earlier years.
The upcoming 2020 census may be flawed too, since some areas will likely be difficult to count. Any area with large numbers of the poor, minorities, immigrants and children is at higher risk of being undercounted in 2020, especially the rural Deep South, according to Tony Pugh of McClatchy Newspapers. An accurate count would be more difficult if the census adds a question about citizenship, possibly causing the country's three most populous states (California, Texas and Florida) to lose seven congressional seats.