The primary data used for this visualization comes from the
ICPSR's tabulations of historical data sets: Haines, Michael
R., and Inter-university Consortium for Political and Social
Research. Historical, Demographic, Economic, and Social Data:
The United States, 1790-2002. ICPSR02896-v3. Ann Arbor, MI:
Inter-university Consortium for Political and Social Research
[distributor],
2010-05-21. http://doi.org/10.3886/ICPSR02896.v3
Historical County boundaries are taken from the Newberry
Library's Atlas of Historical County Boundaries: Siczewicz,
Peter. U.S. Historical Counties (Generalized .01
deg). Dataset. Emily Kelley, digital comp. Atlas of Historical
County Boundaries, ed. by John H. Long. Chicago: The Newberry
Library, 2011. Available online from
http://publications.newberry.org/ahcbp.
This site includes color
specifications and designs developed by Cynthia Brewer
(http://colorbrewer.org/)
It makes use of Javascript frameworks D3 (d3js.org) and jQuery
(jquery.org), as well as the Bootstrap library. A few CSS
styles are borrowed from Elijah Meeks' project d3.carto.map.
The slideshow on population density uses scans of the Census
atlases from David Rumsey historical maps.