Indexed Materials found at Tiffin Seneca Public Library include:

- County Histories (These have a name index)
- History of Seneca County 1880 (Lang)
- History of Seneca County (Baughman)
- Centennial Biographical History of Seneca County - www.kriskuhn.net/1902.htm 
- Between the Eighties - Tiffin, Ohio 1880 -1980 (Barnes)
- Seneca County Ohio - Histories and Families (1998) Genealogy Society
- History of Seneca County - 1886 (Warner-Beers)
Click here for on-line text: www.heritagepursuit.com/Seneca/SenIndex.htm
- Cemetery Inscriptions of Seneca County -1987
- International Genealogical Index - On microfiche by the Church of the Latter Day Saints. Includes a personal-name index, with birth and marriages. For Canada, France, Germany, Ireland, Luxembourg, and Switzerland 1988. For the United States, 1992.
- Seneca County Marriage Index - 1841-1899, 1899-1930, 1957-1977
- Marriage Announcements - 1832-1877, in newspapers on microfilm    
- Births - 1867- 1908, on microfilm. *After 1908 check the health dept.
- Deaths - 1867-1908, on microfilm
- Birth Index for Seneca County
- Obituaries and death notices - Most of T-SPL's obituaries are online at http://index.rbhayes.org/hayes/index/ 
- Divorces - Up to 1911
- Marriage Licenses - 1841-1983, on microfilm with name index up to 1992

- Reunions - 1880-1940

- Wills in Seneca County – Seneca County Probate Court 1851-1900

- Seneca County Probate Court's Administration Docket, Civil Docket 1852-1886  

- Original Land Entries of Seneca County Deed Index - Does not include actual deeds
- Hardesty’s Historical and Geographical Encyclopedia