Sources: U.S. Census Bureau, Census 2020; generated by CCRPC staff; using 2020 Census Demographic Data Map Viewer; https://www.census.gov/library/visualizations/2021/geo/demographicmapviewer.html; (18 August 2021); U.S. Census Bureau; Census 2000, Summary File 1, Table DP-1; generated by CCRPC staff; using American FactFinder; <http://factfinder2.census.gov>;; (30 December 2015). U.S. Census Bureau; Census 2010, Summary File 1, Table P1; generated by CCRPC staff; using American FactFinder; <http://factfinder2.census.gov>;; (30 December 2015). U.S. Census Bureau; 1980 Census of Population, Volume 1: Characteristics of the Population, Chapter A: Number of Inhabitants, Part 15: Illinois, PC80-1-A15, Table 2, Land Area and Population: 1930-1980. U.S. Census Bureau; Fourteenth Census of the United States; State Compendium Illinois, Table 1. - Area and Population of Counties: 1850 to 1920; <https://www.census.gov/library/publications/1924/dec/state-compendium.html>;; (23 August 2018).
