Jefferson County Population 2018
Jefferson County's estimated population is 771,158 with a growth rate of 0.50% in the past year according to the most recent United States census data. Jefferson County is the 1st largest county in Kentucky.
| Year | Population | Growth | Growth Rate |
| 2017 | 771,158 | 3,823 | 0.50% |
| 2016 | 767,335 | 2,994 | 0.39% |
| 2015 | 764,341 | 3,242 | 0.43% |
| 2014 | 761,099 | 3,144 | 0.41% |
| 2013 | 757,955 | 6,578 | 0.88% |
| 2012 | 751,377 | 5,040 | 0.68% |
| 2011 | 746,337 | 4,319 | 0.58% |
| 2010 | 742,018 | 77,081 | 11.59% |
| 1990 | 664,937 | -20,067 | -2.93% |
| 1980 | 685,004 | -10,051 | -1.45% |
| 1970 | 695,055 | 84,108 | 13.77% |
| 1960 | 610,947 | 126,332 | 26.07% |
| 1950 | 484,615 | 99,223 | 25.75% |
| 1940 | 385,392 | 30,042 | 8.45% |
| 1930 | 355,350 | 68,981 | 24.09% |
| 1920 | 286,369 | 23,449 | 8.92% |
| 1910 | 262,920 | 30,371 | 13.06% |
| 1900 | 232,549 | 43,951 | 23.30% |
| 1890 | 188,598 | 42,588 | 29.17% |
| 1880 | 146,010 | 27,057 | 22.75% |
| 1870 | 118,953 | 29,549 | 33.05% |
| 1860 | 89,404 | 29,573 | 49.43% |
| 1850 | 59,831 | 23,485 | 64.62% |
| 1840 | 36,346 | 12,367 | 51.57% |
| 1830 | 23,979 | 3,211 | 15.46% |
| 1820 | 20,768 | 7,369 | 55.00% |
| 1810 | 13,399 | 4,645 | 53.06% |
| 1800 | 8,754 | 3,989 | 83.71% |
| 1790 | 4,765 | 0.00% |