Pennsylvania - Area of significance: Architecture
| Old Kennett Meetinghouse |
| Old Lehigh County Courthouse |
| Old Main |
| Old Main and Chemistry Building |
| Old Main at the Lutheran Home at Topton |
| Old Main, California State College |
| Old Main, Goethean Hall, and Diagnothian Hall |
| Old Mauch Chunk Historic District |
| Old Norriton Presbyterian Church |
| Old Pottstown Historic District |
| Old Rose Tree Tavern |
| Old Stone Arch Bridge |
| Old Swede's House |
| Old Town Historic District |
| Old Uptown Harrisburg Historic District |
| Old West, Dickinson College |
| Old White Mill |
| Oley Township Historic District |
| Oliver, David P., High School |
| Oller, Joseph J., House |
| Olney Elementary School |
| Olney High School |
| Oregon Mill Complex |
| Ormrod, George, House |
| Orris, Adam, House |
| Ortlieb, Henry F., Company Bottling House |
| Osterburg Covered Bridge |
| Osterling, Frederick J., Office and Studio |
| Ostheimer, Martha and Maurice, Estate |
| Overbrook Farms |
| Overbrook Gardens Apartments |
| Overbrook High School |
| Overbrook School |
| Oxford Historic District |
| Oxford Hotel |
| Oyer, Christian, Jr., House |
| Packard Motor Corporation Building |
| Packer, Asa, Mansion |
| Packer, Harry, Mansion |
| Packer, Isaac A., Farm |
| Packer Memorial Chapel |
| Packwood House-American Hotel |
| Pagoda |
| Painter’s Folly |
| Painter, William, Farm |
| Palmer, Amos, House |
| Paradise Valley Historic District |
| Pardee, Israel Platt, Mansion |
| Park Dinor |
| Parker Dam State Park Family Cabin District |
| Parker Dam State Park-Octagonal Lodge |
| Parker Dam State Park-Parker Dam District |
| Parkersville Friends Meetinghouse |
| Parkesburg National Bank |
| Parkhurst Memorial Presbyterian Church |
| Park Place School |
| Parkside Chapel |
| Parkside Historic District |
| Parreco, James, House |
| Parsons-Taylor House |
| Passavant House |
| Passmore, Mansel, House |
| Paterson, John M., School |
| Patterson, Burd, House |
| Patterson, Samuel, House |
| Patton Historic District |
| Paupack School |
| Pawling, Isaac, House |
| Paxson, Isaiah, Farm |
| Payne's Folly |
| Peace Church |
| Peirce, William S., School |
| Pemberton, Phineas, House |
| Penn Alto Hotel |
| Pennell, Joseph, School |
| Penn-Liberty Historic District |
| Pennock E. Sharpless House |
| Pennock, Martha, House |
| Pennsalt Historic District |
| Penn's Cave and Hotel |
| Penn's Park General Store Complex |
| Penns Park Historic District |
| Pennsylvania Academy of the Fine Arts |
| Pennsylvania Chautauqua Historic District |
| Pennsylvania Furnace Mansion |
| Pennsylvania Hall, Gettysburg College |
| Pennsylvania Institute for the Deaf and Dumb |
| Pennsylvania Railroad Freight Building |
| Pennsylvania Railroad GG1 Streamlined Electric Locomotive #4859 |
| Pennsylvania Railroad Office Building |
| Pennsylvania Railroad Passenger Station |
| Pennsylvania Railroad Station |
| Pennsylvania Railroad Station at Wayne |
| Pennsylvania Railroad Station-Latrobe |
| Pennsylvania Railroad Station-Wilkinsburg |
| Pennsylvania State Lunatic Hospital |
| Pennsylvania State Office Building |
| Penn Towers |
| Penn Treaty Junior High School |
| Penn, William, Memorial Museum and State Archives Building |
Data from United States Park Service and Wikidata
