Ohio - Area of significance: Architecture
| Stump, John, House And Mill |
| Sturges, Susan, House |
| Stuyvesant Hall |
| St. Wendelin Catholic Church, School, and Rectory |
| Succesful Sales |
| Summit County Courthouse and Annex |
| Summit Street Young Women's Christian Association (YWCA) |
| Sunbury Tavern |
| Sunbury Town Hall |
| Sunny Knolls-Pape, Gordon E., House |
| Superior Avenue Historic District |
| Superior Avenue Viaduct |
| Sutton House |
| Swetland House |
| Swift-Kinsman House |
| Sycamore-13th Street Grouping |
| Sycamore School |
| Symmes Mission Chapel |
| Taft Museum |
| Talcott, Joseph, House |
| Tallmadge-Mithoff House |
| Tallmadge Town Square Historic District |
| Tambling, Lucius T., House |
| Tangeman, John, House |
| Tanglewood |
| Tannehill, Capt. James Boggs, House |
| Tanner, William C., House |
| Tappan House |
| Tappan, Judge Abraham, House |
| Tavern Club |
| Tawney Musser Farm |
| Taylor, Colonel Joseph, House |
| Taylor-Frohman House |
| Taylor Mansion-Lakehurst |
| Taylorsville Canal Inn |
| Teakwood Heights Historic District |
| Tecumseh Building |
| Telephone Building, Old |
| Telling, William E., House |
| Temperance Row Historic District |
| Templar-Farrell Motor Sales Building |
| Temple on the Heights |
| Temple, The |
| Terrace Plaza Hotel |
| The Broer-Freeman Building |
| Theresa Building |
| The Ridge |
| Third Avenue and North High Historic District |
| Third Church of Christ Scientist |
| Third National Bank |
| Third Presbyterian Church |
| Thomas Select School |
| Thompson-Builder House |
| Thompson-Bullock House |
| Thompson, Cassius Clark, House |
| Thompson, Enoch, House |
| Thompson Farm |
| Thomson, Peter G., House |
| Thornton-Guise Kitchen And House |
| Thorp, Manville, Residence |
| Thorp, W. A., House |
| Thrush, Morgan, Farm Complex |
| Thumann Log House |
| Thurber, James, House |
| Thurston Building |
| Tiedemann, Hannes, House |
| Tiffin Agricultural Works |
| Tiffin Art Metal Company |
| Tiffin Waterworks |
| Tilden, Daniel, House |
| Times Building-Lodge Hall |
| Times-Star Building |
| Timken, Henry H., Estate Barn |
| Timken Vocational High School |
| Tod Homestead Cemetery Gate |
| Toledo and Ohio Central Depot |
| Toledo and Ohio Central Railroad Station |
| Toledo Central Business Historic District |
| Toledo Club |
| Toledo Olde Towne Historic District |
| Toledo Traction Company Power Station |
| Toledo Yacht Club |
| Tonkens, Gerald B. and Beverley, House |
| Tower East |
| Towers Hall, Otterbein College |
| Town Center District |
| Townes, Clayton, House |
| Town Hall |
| Townsend, William T., House |
| Traction Company Building |
| Trailsend |
| Travellers' Rest Inn |
| Traxler Mansion |
| Tremaine-Gallagher Residence |
| Tremont Historic District |
| Tremont House |
| Trimble, James S., House |
| Trinity Cathedral |
| Trinity Cathedral Church Home |
| Trinity Episcopal Church |
Data from United States Park Service and Wikidata
