Ohio - Area of significance: Social History
| Mountain House |
| Mount Airy Forest |
| Mount Auburn Historic District |
| Mount Pleasant Historic District |
| Mumma, Jacob H. W., House |
| National Home, Daughters of America |
| National Orphans' Home, Junior Order United American Mechanics |
| New England Lodge |
| New Garden Monthly Meetinghouse |
| Newport Village Allotment Historic District |
| Newton Falls United Service Organization (USO) Center |
| Ninth Street Historic District |
| No. 5 Fire Station |
| Noble County Jail and Sheriff's Office |
| Noble, Jonathan, House |
| Northfield Town Hall |
| North Presbyterian Church |
| Northrop, Julia Carter, House |
| North Union Shaker Site |
| Nurre-Royston House |
| Oberlin College |
| Odd Fellows' Home for Orphans, Indigent and Aged |
| Odd Fellows Temple |
| Ohio City Preservation District |
| Ohio Institution for the Education of the Deaf and Dumb |
| Ohio State Reformatory |
| Ohio Wesleyan University Fraternity Hill Historic District |
| Old St. Mary's Church, School and Rectory |
| Old Wood County Jail |
| O. P. Boyer’s and Sons Funeral Home |
| Oregon Historic District |
| Osborn, Charles S., House |
| Overlook Road Carriage House District |
| Over-the-Rhine Historic District |
| Ozmun, Isaac and Maria, Farmstead |
| Palace Theater |
| Parker, John P., House |
| Parker, John P., House |
| Patterson, Mary A., Memorial |
| Paulding County Carnegie Library |
| Peninsula Village Historic District |
| Pennsylvania Railroad Depot And Baggage Room |
| Phoenix Building/Cincinnati Club |
| Pickerington Carnegie Library |
| Pilgrim Congregational Church |
| Piqua Historical Area State Memorial |
| Pleasant Hill |
| Pollack, Isaac, House |
| Pomeroy, Alanson, House |
| Portage Hotel |
| Port Clinton City Hall |
| Port Washington Town Hall |
| Potter’s Field - West Price Hill |
| Pythian Castle |
| Pythian Temple and James Pythian Theater |
| Radnor Township Hall |
| Raemelton Farm Historic District |
| Railway Chapel, The |
| Rankin, John, House |
| Rawson House |
| Record Rendezvous |
| Red Oak Presbyterian Church |
| Red Popcorn Wagon |
| Reed, C. A., House |
| Reed, Henry, Jr., House |
| Rhodes and Watters Apartment Buildings, The |
| Rial, York, House |
| Richland County Infirmary |
| Ripley Historic District |
| Rose Hill and Community House |
| Salem Bear Creek Church, Salem Evangelical Lutheran Church |
| Sandusky County Jail and Sheriff's House |
| Schoenbrunn Site |
| Schooley, Dr. Lindley, House and Office |
| Scioto Grange No. 1234 |
| Second Baptist Church |
| Second Baptist Church |
| Seely, Dr. John W., House |
| Sells, Benjamin, House |
| Sells, William Henry, House |
| Seymour, William H., House |
| Sharon Township Town Hall |
| Shawen Acres |
| Sheltering Arms Hospital |
| Shiloh Baptist Church |
| Sidaway Bridge |
| Sig's General Store |
| Sloane, Rush R., House |
| Smead, David, House |
| Smith, Dr. Robert and Anne House |
| Snow, John, House |
| Snow, Russ and Holland, Houses |
| Southern Ohio Lunatic Asylum |
| South Leroy Meetinghouse |
| South Main Street District |
| South Newbury Union Chapel |
| South Park Historic District |
| Springboro Historic District |
| Springfield Township School |
| Spring Hill |
Data from United States Park Service and Wikidata
