Riley County, Kansas Population 2019
Riley County, Kansas's estimated population is 73,982 with a growth rate of -1.57% in the past year according to the most recent United States census data. Riley County, Kansas is the 7th largest county in Kansas.
| Year | Population | Growth | Growth Rate |
| 2018 | 73,703 | -279 | -0.38% |
| 2017 | 73,982 | -1,181 | -1.57% |
| 2016 | 75,163 | -1,986 | -2.57% |
| 2015 | 77,149 | 664 | 0.87% |
| 2014 | 76,485 | -451 | -0.59% |
| 2013 | 76,936 | -563 | -0.73% |
| 2012 | 77,499 | 4,080 | 5.56% |
| 2011 | 73,419 | 1,866 | 2.61% |
| 2010 | 71,553 | 4,414 | 6.57% |
| 1990 | 67,139 | 3,634 | 5.72% |
| 1980 | 63,505 | 6,717 | 11.83% |
| 1970 | 56,788 | 14,874 | 35.49% |
| 1960 | 41,914 | 8,509 | 25.47% |
| 1950 | 33,405 | 12,788 | 62.03% |
| 1940 | 20,617 | 735 | 3.70% |
| 1930 | 19,882 | -768 | -3.72% |
| 1920 | 20,650 | 4,867 | 30.84% |
| 1910 | 15,783 | 1,955 | 14.14% |
| 1900 | 13,828 | 645 | 4.89% |
| 1890 | 13,183 | 2,753 | 26.40% |
| 1880 | 10,430 | 5,325 | 104.31% |
| 1870 | 5,105 | 3,881 | 317.08% |
| 1860 | 1,224 | 0.00% |