African-American Genealogical Society of Cleveland, Ohio
Canal Society of Ohio  a non-profit organization for the purpose of preserving Ohio canal history and to increase interest in canal heritage
Genealogy by Computer Society  serving NW Ohio and SE Michigan
Irish American Archives Society establshed in 1994 for the purpose of establishing and maintaining an Archives to collect, preserve and make available for research the papers, documents, photographs and memorabilia of Irish individuals and families and the records of Irish organizations and institutions that have influenced the growth and development of the Irish American community in northeast Ohio
Ohio Genealogical Society
Ohio Historical Society
 Ohio Society Children of the American Revolution
Ohio Society of the War of 1812
Old Northwest Historical Society The Old Northwest Historical Society is an educational organization dedicated to preserving and perpetuating the history of the Old Northwest Territory.This is the region northwest of the Ohio river that became the states of Ohio, Indiana, Illinios, Michigan, and Wisconsin
Slovenian Genealogy Society, Ohio Chapter

Additional Resources at Ancestry.com

Ohio Censuses, 1790-1890
Ohio Early Land Ownership Records each record provides the landowner's name, town of residence, and number of shares allotted
Ohio Marriages, 1803-1900
Ohio State Databases over 200 databases for Ohio here including military rosters, censuses, marriage and birth records