Ohio
- History
- 1895 Atlas: Ohio
- African-American Experience in Ohio 1850-1920
- American History and Genealogy Project: Ohio
- American Local History Network: Ohio
- Ashtabula County Historical Society
- Athens County Historical Society & Museum
- Athens Photo Gallery
- Aurora Historical Society
- Berea Historical Society
- The Biographical Encyclopedia of Ohio of the Nineteenth Century (1876)
- Black River Historical Society
- Black River Historical Society Photo Archive
- Bridges of Cleveland and Cuyahoga County
- Buckeye Chronicles
- Bucyrus Historical Society
- By the Neck Until Dead: A History of Hangings in Cuyahoga County
- Caldwell's 1874 Atlas of Ashland County, Ohio
- Camp Chase Military Prison & Confederate Cemetery
- Canton 1914 City Directory
- Case Western Reserve University - Books on Cleveland
- Centennial History of Cleveland, Ohio (1896)
- Chillicothe 1928 City Directory
- Cincinnati Fire Departmant History
- Civil War Documents
- Civil War Ohio
- Civil War Regimental History: Ohio
- Civil War Rosters: Ohio
- Cleveland 1900 City Directory
- Cleveland: Confused City on a Seesaw (1976)
- Cleveland Digital Library
- Cleveland Heights Historical Society
- Cleveland Memory Project
- Cleveland News Index
- Cuyahoga County Ohio 1900 Census
- Cyndi's List of Genealogy Sites on the Internet: Ohio
- Discover Ohio: Genealogy
- Discover Ohio: History
- The Earliest Settlement In Ohio (1885)
- Early History of Cleveland, Ohio (1867)
- Early History of Ohio (1841)
- Early History of Ohio (1854)
- Earthquake History of Ohio
- Encyclopedia of Cleveland History
- Erie County 1905 Rural Mail Directory
- Evolution of Ohio
- Fifty Years of Ohio (1838)
- Fight for the Colors: Ohio Battle Flag Collection
- Findlay 1927 Directory
- GeneaSearch: Ohio
- Google: Ohio - History
- Governors of Ohio, 1803-1971
- Great Lakes Maritime Personnel Online Database
- Great Lakes Online Ports Database
- Great Lakes Vessels Online Image Database
- Greenhills Historical Society
- Hancock County 1927 Directory
- Heritage Ohio
- Heritage Pursuit
- Historic Rutland: The Cradle of Ohio (1893)
- Historic Woodlawn Cemetery
- Historical Collections of Ohio
- Historical Museum Guide for Ohio
- History and Biographical Cyclopedia of Butler County, Ohio
- History of Crawford and Ohio
- History of Knox County, Ohio, From 1779 to 1862 Inclusive
- History of Lorain
- History of the State of Ohio ... First Period, 1650-1787 (1854)
- History of Wayne County, Ohio (1878)
- Huron County 1905 Rural Mail Directory
- Kindred Trails: Ohio
- Lancaster 1924/25 City Directory - Index
- Northeast Ohio Journal of History
- Ohio Biography
- Ohio Cemeteries
- Ohio Census Records
- Ohio City Directories
- Ohio Genealogical and Historical Societies
- Ohio Ghost Towns
- Ohio Historical Center
- Ohio Historical Societies
- Ohio Historical Society
- Ohio History Central
- Ohio History Online
- Ohio in the Civil War
- Ohio Listings on the National Register of Historic Places
- Ohio Memory
- Ohio Migrations
- Ohio Museums Guide
- Ohio Newspaper Index
- Ohio Obituary Links
- Ohio State Gazetteer and Business Directory for 1860-61
- Ohio Tornadoes 1950-1995
- OhioPix
- Ohio's First Capital (1881)
- Perry-Castaņeda Library Map Collection: Ohio
- Political Graveyard: Ohio
- Portage County Historical Society
- Portage County Marriages
- Primary Resources for Teachers
- Repositories of Primary Sources
- Saint Albert's Cemetery Records, Brea
- Saint Mary's Cemetery& Baptism Records, Minerton
- Shelby County Historical Society
- Shelby County Historical Society Archives
- Sketches and Statistics of Cincinnati in 1851
- Strongville Cemetery Records 1818-2001
- Toledo Profile: a Sequicentennial History
- Toledo's Attic
- Tribes and Villages of Ohio
- United States Resources: Ohio
- USGenWeb Ohio Archives
- Worthington Cemeteries
- Worthington Memory
- Yahoo!: Ohio - History