Pennsylvania - Significance region: Local
| Silver Lake Schoolhouse #1 |
| Simon, Herman, House |
| Simon, R. and H., Silk Mill |
| Simpson Street School |
| Singer, John F., House |
| Sinking Springs Farms |
| Sinnott, Joseph, Mansion |
| Sixteenth Street Bridge |
| Sixth Ward School |
| Skinner Tavern |
| S.L. Allen & Company Building |
| Slate Hill Cemetery |
| Slater Cigar Company |
| Sleepy Hollow Hall |
| Slifer House |
| Slusher, David, Farm |
| Smalley, Lewis, Homestead |
| Smaltz Building |
| Smedley, Franklin, School |
| Smith Family Farmstead |
| Smith, Henry, Farm |
| Smith, Walter George, School |
| Smith, William, House |
| Smyser and English Pharmacy |
| Snellenburg's Clothing Factory |
| Snooks Covered Bridge |
| Snyder, Caspar, House |
| Snyder Covered Bridge No. 17 |
| Snyder Mill |
| Snyder, William Penn, House |
| Social Service Building |
| Sodom Schoolhouse |
| Solitude Farm |
| Somerset County Courthouse |
| Sonestown Covered Bridge |
| Sotcher Farmhouse |
| Souderton Historic District |
| Southampton Baptist Church and Cemetery |
| South Bethlehem Downtown Historic District |
| South Road Bridge, Northern Central Railway |
| South Side High School |
| South Side Market Building |
| South Ward School |
| Southwark School |
| South Wayne Historic District |
| Spalding Memorial Library-Tioga Point Museum |
| Spangler-Benner Farm |
| Spangler, George Christian and Anna Catherine, Farm |
| Spannuth Mill |
| Speedwell Forge Mansion |
| Sperling Building |
| Spicker, Peter, House |
| Sprenger Brewery |
| Springdale Historic District |
| Springdale Historic District |
| Springdale Mills |
| Springer Farm |
| Springfield Mill |
| Springfield Public School |
| Spring Garden School No. 1 |
| Spring Garden School No. 2 |
| Spring Grove Borough Historic District |
| Spring Grove Farm and Distillery |
| Spring Grove Forge Mansion |
| Spring Mill Complex |
| Springton Manor Farm |
| Springtown Historic District |
| Spring Valley Historic District |
| Sprowl's Covered Bridge |
| Spruce Creek Rod and Gun Club |
| Spruce Grove School |
| Square Tavern |
| Stanley |
| Stanley Theater and Clark Building |
| St. Anthony de Padua Parish School |
| St. Anthony Hall House |
| Stanton, Edwin M., School |
| Stanton, M. Hall, Public School |
| Star Barn Complex |
| Star Carpet Mill |
| Star Junction Historic District |
| Starlight Station, New York, Ontario, and Western Railway |
| State Theatre |
| Stauffer, Christian, House |
| Stauffer, Dr. B., House |
| St. Augustine's Catholic Church |
| St. Boniface Roman Catholic Church |
| Steckel, Daniel, House |
| Steel Heddle Manufacturing Company Complex |
| Steelton High School |
| Steen, Robert, House |
| Steinman Hardware Store |
| Stein Mill |
| St. Elisabeth’s Episcopal Church |
| St. Elizabeth's Convent |
| Stephenson-Campbell House |
| Sterrett Sub-District School |
| Stevens High School |
| Stevens School |
| Stevens, Thaddeus, School of Observation |
Data from United States Park Service and Wikidata
