Formed 30 Jan 1808, 531 square miles
Parent counties: Fairfield, Franklin
Evolution of county from date of formation until it assumed its final form
1 Mar 1808: Erected and organized. Richland attached temporarily until organization
1 Mar 1813: Diminished by organization of Richland
1 Mar 1848: Diminished by formation of Morrow
Federal Population schedules extant from 1820-1940. (1890 missing) Part of Knox was in Washington County, the only county with the 1800 census surviving.
1820 Manufacturers; 1850 Agricultural; 1850 Industry; 1850 Mortality; 1860 Agricultural, 1860 Mortality; 1870 Agricultural; 1880 Agricultural; 1880 Defective, Dependent, and Delinquent
Berlin, Brown, Butler, Clay, Clinton, College, Harrison, Hilliar, Howard, Jackson, Jefferson, Liberty, Middlebury, Milford, Miller, Monroe, Morgan, Morris, Pike, Pleasant, Union, and Wayne.
Jana Broglin, OGSF