Mercer County, Kentucky (Formed 1786)
                Land Area          
Year  Population  (sq.mi)   Density
2010     21,331     248.8     85.7
2000     20,817     250.9     83.0
1990     19,148     250.9     76.3
1980     19,011     250.9     75.8
1970     15,960     250.9     63.6
1960     14,596     250.9     58.2
1950     14,643     250.9     58.4
1940     14,629     250.9     58.3
1930     14,471     250.9     57.7
1920     14,795     250.9     59.0
1910     14,063     253.0     55.6
1900     14,426     254.0     56.8
1890     15,034     254.0     59.2
1880     14,142     252.4     56.0
1870     13,144     252.4     52.1
1860     13,701     252.6     54.2
1850     14,067     252.4     55.7
1840     18,720     394.5     47.5
1830     17,694     431.5     41.0
1820     15,587     483.8     32.2
1810     12,630     457.9     27.6
1800      9,646     465.3     20.7
1790      7,091     647.8     10.9