Johnson County, Kentucky (Formed 1843) Land Area Year Population (sq.mi) Density 2010 23,356 262.0 89.2 2000 23,445 261.5 89.6 1990 23,248 261.6 88.9 1980 24,432 261.6 93.4 1970 17,539 261.6 67.0 1960 19,748 261.6 75.5 1950 23,846 261.6 91.2 1940 25,771 261.6 98.5 1930 22,968 261.6 87.8 1920 19,622 261.6 75.0 1910 17,482 268.0 65.2 1900 13,730 266.0 51.6 1890 11,027 266.0 41.5 1880 9,155 259.0 35.3 1870 7,494 259.0 28.9 1860 5,306 444.5 11.9 1850 3,873 432.9 8.9