Divergence in U.S. Sex Ratios by County, 1820–2010

How to use this map

This map shows U.S. counties that diverged from an equal (or nearly equal) sex ratio. Counties shown in white had a sex ratio of no more than 51 percent male or female. Counties shown in green had a higher proportion of males; counties shown in brown had a higher proportion of females.

I wrote a brief blog post about the map.

Map by Lincoln Mullen. Code available on GitHub, licensed MIT. Suggestions and criticism welcome: lincoln@lincolnmullen.com.


If you use this map in your research, I would appreciate a citation. Here is the suggested form:

Lincoln Mullen, "Divergence in U.S. Sex Ratios by County, 1820–2010," interactive map, http://lincolnmullen.com/projects/sex-ratios/.

You should also cite the NHGIS, who provided the data:

Minnesota Population Center, National Historical Geographic Information System: Version 2.0 (Minneapolis, MN: University of Minnesota, 2011), http://www.nhgis.org.