Pennsylvania - Area of significance: Engineering
| Pine Valley Covered Bridge |
| Pithole Stone Arch |
| Pittsburgh and Lake Erie Railroad Complex |
| Pleasantville Bridge |
| Pond Eddy Bridge |
| Pond Mill Bridge |
| Pool Forge Covered Bridge |
| Pottstown Roller Mill |
| Presque Isle Light |
| Quaker Bridge |
| Rapp's Bridge |
| Reading-Halls Station Bridge |
| Reading Terminal and Trainshed |
| Red Run Covered Bridge |
| Rex Covered Bridge |
| Richmond Station, Philadelphia Electric Company |
| Ridge Avenue Bridge in Philadelphia |
| Ridge Road Bridge, Stewartstown Railroad |
| Ridgway Armory |
| Riegel Covered Bridge No. 6 |
| Rockland Furnace |
| Rockville Bridge |
| Roebling, John, House |
| Rohrbach Covered Bridge No. 24 |
| Ross Furnace |
| Runk Bridge |
| Rupert Covered Bridge No. 56 |
| Ryot Covered Bridge |
| Saxonburg Historic District |
| """S"" Bridge" |
| S Bridge |
| Schlicher Covered Bridge |
| Schubert-Graber Log-Post Shop |
| Scott Creek Bridge-North, Maryland and Pennsylvania Railroad |
| Second Street Bridge |
| Seigrist's Mill Covered Bridge |
| Seventh Street Bridge |
| Seyfert Mill |
| Shade Gap Feed and Flour Mill |
| Shaffer's Bridge |
| Shaw Historic District |
| Sheard's Mill Covered Bridge |
| Shearer's Covered Bridge |
| Shenk's Mill Covered Bridge |
| Shoaf Historic District |
| Shoemaker Covered Bridge |
| Sixteenth Street Bridge |
| Sixth Street Bridge |
| Skippack Bridge |
| Smithfield Street Bridge |
| Snooks Covered Bridge |
| Snyder Covered Bridge No. 17 |
| Snyder Mill |
| Soldiers and Sailors Memorial Bridge |
| South Perkasie Covered Bridge |
| South Road Bridge, Northern Central Railway |
| Speakman No. 1 |
| Speakman No. 2, Mary Ann Pyle Bridge |
| SS UNITED STATES (Steamship) |
| Staple Bend Tunnel |
| Starrucca Viaduct |
| St. Boniface Roman Catholic Church |
| Stephens, Linton, Covered Bridge |
| Stillwater Covered Bridge No. 134 |
| St. Mary's Covered Bridge |
| Stoddartsville Historic District |
| Stone Arch Road Bridge, Stewartstown Railroad |
| St. Vincent Archabbey Gristmill |
| Sutch Road Bridge in Marlborough Township |
| Swamp Creek Road Bridge |
| Swatara Furnace |
| Terminal Commerce Building |
| The Elverson Building |
| Thirty-third Street Bridge in Philadelphia |
| Thomas Covered Bridge |
| Thomas Mill Covered Bridge |
| Thompson Mill |
| Trostletown Bridge |
| Trusal Covered Bridge |
| Tunkhannock Viaduct |
| Twin Bridges-East Paden Covered Bridge No. 120 |
| Twin Bridges-West Paden Covered Bridge No. 121 |
| Union Canal Tunnel |
| University Avenue Bridge |
| USS BECUNA (SS-319) |
| Valley Road Bridge, Stewartstown Railroad |
| Van Sant Covered Bridge |
| Wagner Covered Bridge No. 19 |
| Wagner, John and Family Farmstead |
| Walnut Street Bridge |
| Walnut Street Bridge |
| Walter's Mill Bridge |
| Wanich Covered Bridge No. 69 |
| Warrior Ridge Dam and Hydroelectric Plant |
| Waterford Covered Bridge |
| Waterville Bridge |
| Watsontown River Bridge |
| Weaver's Mill Covered Bridge |
| Webster Donora Bridge |
| Wehr Covered Bridge |
Data from United States Park Service and Wikidata
