Oregon - Criteria: C (architecture/engineering)
| Newman United Methodist Church |
| New Redmond Hotel |
| New Taggart Hotel |
| Nicholas-Lang House |
| Nichols, Dr. Herbert S., House |
| Nicolai-Cake-Olson House |
| Nicolai, Harry T., House |
| North Fork of the Yachats Bridge |
| Northwestern Electric Company-Alberta Substation |
| Northwestern National Bank Building |
| Oak Hills Historic District |
| Oakland Historic District |
| Odd Fellows Building |
| Odd Fellows Rural Cemetery |
| Odem, Milton, House |
| O'Donnell, E. J., House |
| Office Bridge |
| O'Kane Building |
| Olallie Lake Guard Station |
| Old First National Bank Building |
| Old First National Bank of Prineville, and Foster and Hyde Store |
| Old Garfield School |
| Old Scotch Church |
| Olds, Wortman and King Department Store |
| Old Town Historic District |
| Old US Post Office |
| Old Yaquina Bay Lighthouse |
| Oleson, Ole and Polly, Farmhouse |
| Olson, August, House |
| Olson, Charles and Fae, House |
| Olympic Apartment Building |
| Olympic Cereal Mill |
| Oregon Caves Chateau |
| Oregon City Carnegie Library |
| Oregon City Municipal Elevator |
| Oregon Cracker Company Building |
| Oregon Electric Railway Passenger Station |
| Oregon Portland Cement Building |
| Oregon Railway and Navigation Company Bridge |
| Oregon Short Line Railroad Depot |
| Oregon State Capitol |
| Oregon State Fair Stadium and Poultry Building Ensemble |
| Oregon State Forester's Office Building |
| Oregon State Hospital Historic District |
| Oregon State Soldier's Home Hospital |
| Oregon State University Historic District |
| Oregon Trunk Passenger and Freight Station |
| Oregon-Washington Railroad & Navigation Company Passenger Station |
| Oriental Apartments |
| Ormonde Apartment Building |
| Osborn Hotel |
| Otis Elevator Company Building |
| Ott, David and Marianne, House |
| Our Lady of Perpetual Help Roman Catholic Church |
| Owyhee Dam Historic District |
| Pacific Building |
| Pacific Coast Biscuit Company Building |
| Pacific Hardware and Steel Company Warehouse |
| Packard Service Building |
| Page and Son Apartments |
| Palace Hotel |
| Palmer House |
| Palmer, John, House |
| Paramount Theatre |
| Parelius, Martin, Fourplex |
| Parker Meadows Shelter |
| Parrott, Moses, House |
| Parsons, John and Elsie, House |
| Parvin Bridge |
| Paterson, Thomas M. and Alla M., House |
| Patterson-Stratton House |
| Paulina Lake Guard Station |
| Peacock Lane Historic District |
| Peck Bros. and Bartle Tire Service Company Building |
| Peery, E.C., Building |
| Pelota Fronton |
| Pengra Bridge |
| Pernot, Dr. Henry S., House |
| Peters, A. V., House |
| Petersen Rock Garden |
| Petzold, Richard B., Building |
| Phillips, John, House |
| Pioneer Courthouse |
| Pioneer Hall, Linfield College |
| Piper, Charles, Building |
| Pipes, George, House |
| Pipes, Martin Luther, House |
| Pittock Block |
| Pittock Mansion |
| Pleasant Grove Presbyterian Church |
| Polhemus, James S., House |
| Poole, Otho, House |
| Port, Dr. Luke A., House |
| Portland and Southwestern Railroad Tunnel |
| Portland Art Museum |
| Portland City Hall |
| Portland Fire Station No. 17 |
| Portland Fire Station No. 23 |
| Portland Fire Station No. 7 |
| Portland Garden Club |
Data from United States Park Service and Wikidata
