Allen County, Kentucky (Formed 1815)
                Land Area          
Year  Population  (sq.mi)   Density
2010     19,956     344.3     58.0
2000     17,800     346.1     51.4
1990     14,628     346.1     42.3
1980     14,128     346.1     40.8
1970     12,598     346.1     36.4
1960     12,269     346.1     35.4
1950     13,787     346.1     39.8
1940     15,496     346.1     44.8
1930     15,180     346.1     43.9
1920     16,761     346.1     48.4
1910     14,882     394.0     37.8
1900     14,657     428.0     34.2
1890     13,692     428.0     32.0
1880     12,089     346.8     34.9
1870     10,296     346.8     29.7
1860      9,187     348.3     26.4
1850      8,742     346.9     25.2
1840      7,329     348.3     21.0
1830      6,485     348.3     18.6
1820      5,327     267.7     19.9