Ohio - Area of significance: Architecture
| Robinson-Pavey House |
| Rochester Square Historic District |
| Rock Creek School |
| Rockefeller Building |
| Rock Hill Presbyterian Church |
| Rock Hollow School |
| Rock Mill |
| Rodrick Bridge |
| Rogers House |
| Rohr, David, Mansion And Carriage House |
| Rookwood Pottery |
| Root, A. I. And E. R., Homestead |
| Root and McBride-Bradley Building |
| Root, Joseph, House |
| Root, William H., House |
| Ropes, Nathaniel, Building |
| Roscoe Village |
| Rose, Capt. Levi, House |
| Roseville High School |
| Ross Hardware |
| Rossville Historic District |
| Roudebush Farm |
| Round Barn |
| Round Barn |
| Round Barn |
| Round Barn |
| Round Barn |
| Round Hill |
| Roundwood Manor at Daisy Hill Farm |
| Royalton House |
| Rubicon Farm |
| Ruggles, Charles, House |
| Rummell Mill |
| Rush Creek Village Historic District |
| Rushville Historic District |
| Russell, Charles B., House |
| Russell, Mark, House |
| Sachs and Pruden Ale Company Building |
| Sacred Heart Academy |
| Sacred Heart Church |
| Sacred Heart of Jesus Churches |
| Sacred Heart of Jesus Rectory |
| Sage House |
| Sail Loft |
| Saint Anne's Hill Historic District |
| Saint John the Evangelist Catholic Church Complex |
| Saint Joseph's Catholic Church |
| Saint Joseph's Roman Catholic Church |
| Saint Mary's Episcopal Church and Parish House |
| Saint Paul's Episcopal Church |
| Saint Peter and Saint Paul Historic District-Oliver's Second addition |
| Saint Philip's Episcopal Church |
| Salem Bear Creek Church, Salem Evangelical Lutheran Church |
| Salem Church |
| Salem Downtown Historic District |
| Salem Methodist Church Complex |
| Salem Methodist Episcopal Church |
| Salt House |
| Sanborn Hall |
| Sandiford, Robert, House |
| Sands, George F., School |
| Sandusky County Jail and Sheriff's House |
| Sandusky Street Historic District |
| Sarchet-Burgess House |
| Sarchet, Peter B., House |
| Satterthwaite, John, House |
| Saunders, Elizabeth Sheets, Farm |
| Savage-Stewart House |
| Sawyer-Curtis House |
| Sawyer, Louis, House |
| Sawyer-Wayside House |
| Saxony Apartment Building |
| Scarlet Oaks |
| Schafer House |
| Schaller Memorial Building |
| Schantz, Adam Sr., House |
| Schantz Park Historic District |
| Schine's Holland Theatre |
| Schine State Theatre |
| Schlee Brewery Historic District |
| Schlee-Kemmler Building |
| Schmick, Charles Nelson, House |
| Schooley, Dr. Lindley, House and Office |
| Schriber, Hyman, Building |
| Schrock, Peter, Jr., Farm |
| Schueller, Erwin W., House |
| Schuffenecker, August Building |
| Schuter Carpenter Shop and House |
| Schweinfurth, Charles, House |
| Science Hill School |
| Scioto County Courthouse |
| Scioto Street Historic District |
| Scioto Township District No. 2 Schoolhouse |
| Scofield, Levi, House |
| Scofield-Sanor House |
| Scott, George, House |
| Scott, John, Barn and Granary |
| Scott, Matthew, House |
| Scott, William, House |
| Scroggs House |
Data from United States Park Service and Wikidata
