Ohio - Criteria: A (event)
| Prentiss, Frederick, House |
| Prentiss-Tulford House |
| Presbyterian Parsonage |
| Principal's Cottage |
| Procter and Collier-Beau Brummell Building |
| Provident Savings Bank and Trust Co. |
| Putnam Historic District |
| Pythian Castle |
| Pythian Temple and James Pythian Theater |
| Quaker Oats Cereal Factory |
| Race Street Historic District |
| Raemelton Farm Historic District |
| Ragersville School |
| Railway Chapel, The |
| Rawson House |
| Rayen School |
| Raymond, Liberty G., Tavern and Barn |
| Record Rendezvous |
| Red Popcorn Wagon |
| Reidy Bros. & Flanigan Building |
| Rhodes and Watters Apartment Buildings, The |
| Richards-Sewall House |
| Rich, Charles B., House |
| Richman Brothers Company, The |
| Riddle Block |
| Riddle Block #5 |
| Rider, Adam, House |
| Riley, Calvin E., House |
| Rinard Covered Bridge |
| Riverview |
| Roas-Ilhardt Farm and Winery |
| Rock Creek School |
| Rockefeller Park and Cleveland Cultural Gardens Historic District |
| Rock Mill |
| Root and McBride-Bradley Building |
| Roscoe Village |
| Rose Hill and Community House |
| Rossville Historic District |
| Round Barn |
| Round Barn |
| Round Barn |
| Round Barn |
| Round Barn |
| Sachs and Pruden Ale Company Building |
| Sacred Heart of Jesus Churches |
| Sail Loft |
| Saint Anne's Hill Historic District |
| Saint Paul's Episcopal Church |
| Salem Bear Creek Church, Salem Evangelical Lutheran Church |
| Salem Downtown Historic District |
| Sanborn Hall |
| Sands, George F., School |
| Sandusky County Jail and Sheriff's House |
| Sandusky Street Historic District |
| Satterthwaite, John, House |
| Saunders, Elizabeth Sheets, Farm |
| Saunders Seed Company |
| Savage-Stewart House |
| """S"" Bridge II" |
| S Bridge, National Road |
| Schrock, Peter, Jr., Farm |
| Schueller, Erwin W., House |
| Schuffenecker, August Building |
| Science Hill School |
| Scioto Grange No. 1234 |
| Scofield-Sanor House |
| Scott, John, Barn and Granary |
| Second Baptist Church |
| Second Baptist Church |
| Secor Hotel |
| Secor, Joseph K., House |
| Selby Field |
| Selby Shoe Company Building |
| Selle Gear Company |
| Seymour, William H., House |
| Sharon Township Town Hall |
| Sharp-Page House |
| Shawen Acres |
| Shedd-Dunn House |
| Sheffield Village Hall |
| Shelby House |
| Sheltering Arms Hospital |
| Shepard Street School |
| Shield's Block |
| Shield's, Edwin M., House |
| Shier, Carl H., House |
| Shiloh Baptist Church |
| Shinn Covered Bridge |
| Shipherd, John J., House |
| Short North Historic District |
| SHOWBOAT MAJESTIC |
| Shuey's Mill |
| Shull-Lugenbuhl Farm |
| Sidney Walnut Avenue Historic District |
| Sidney Waterworks And Electric Light Building |
| Sig's General Store |
| Slocum Hall |
| Smart Building |
| Snider, Dan F., Ford Dealership Building |
| Snow, Russ and Holland, Houses |
Data from United States Park Service and Wikidata
