Formed 12 Feb 1820, 410 square miles
Parent counties: Shelby, Logan, Mercer
Evolution of county from date of formation until it assumed its final form
1 Mar 1820: Erected and attached to Shelby
1 Mar 1828: Attached to Mercer
1 Mar 1831: Organized
14 Feb 1848: Diminished by formation of Auglaize. Parts of Putnam, Van Wert, and Mercer attached
Federal population schedules extant 1820-1940 (1890 missing) In 1820, the northern part of Allen County was located within Wood County. Wood County's census records for 1820 were lost.
1820 Manufacturers (part of Shelby); 1850 Agricultural; 1850 Industry; 1860 Agricultural; 1860 Mortality; 1870 Agricultural; 1870 Industry; 1880 Mortality
Amanda, American, Auglaize, Bath, Jackson, Marion, Monroe, Perry, Richland, Shawnee, Spencer, and Sugar Creek.
Archival District: Bowling Green State University, Center for Archival Collections, Jerome Library, Bowling Green Ohio.
301 N. Main St., Lima, Ohio 45801-4456
Allen County Museum
620 W. Market St., Lima, Ohio
Allen County Genealogical Society
Jana Broglin, OGSF