Harper County Population 2018
Harper County's estimated population is 5,590 with a growth rate of -1.58% in the past year according to the most recent United States census data. Harper County is the 63rd largest county in Kansas.
| Year | Population | Growth | Growth Rate |
| 2017 | 5,590 | -90 | -1.58% |
| 2016 | 5,680 | -103 | -1.78% |
| 2015 | 5,783 | -49 | -0.84% |
| 2014 | 5,832 | -11 | -0.19% |
| 2013 | 5,843 | -20 | -0.34% |
| 2012 | 5,863 | -75 | -1.26% |
| 2011 | 5,938 | -70 | -1.17% |
| 2010 | 6,008 | -1,116 | -15.67% |
| 1990 | 7,124 | -654 | -8.41% |
| 1980 | 7,778 | -93 | -1.18% |
| 1970 | 7,871 | -1,670 | -17.50% |
| 1960 | 9,541 | -722 | -7.03% |
| 1950 | 10,263 | -1,805 | -14.96% |
| 1940 | 12,068 | -755 | -5.89% |
| 1930 | 12,823 | -833 | -6.10% |
| 1920 | 13,656 | -1,092 | -7.40% |
| 1910 | 14,748 | 4,438 | 43.05% |
| 1900 | 10,310 | -2,956 | -22.28% |
| 1890 | 13,266 | 9,133 | 220.98% |
| 1880 | 4,133 | 0.00% |