Washington - Criteria: C (architecture/engineering)
| Nisqually Entrance Historic District |
| Nooksack Falls Hydroelectric Power Plant |
| North 21st Street Bridge |
| North 23rd Street Bridge |
| North Bend Ranger Station |
| North Coast Casket Company Building |
| North Creek School |
| Northern Life Tower |
| North Fork Quinault Ranger Station |
| North Fork Sol Duc Shelter |
| North Mowich Trail Shelter |
| North Slope Historic District |
| Nuclear Reactor Building |
| Officers Row, Fort Vancouver Barracks |
| Ohanapecosh Comfort Station No. O-302 |
| Ohanapecosh Comfort Station No. O-303 |
| Okanogan County Courthouse |
| Okanogan Project: Conconully Resevoir Dam |
| Old City Hall |
| Old City Hall Historic District |
| Old Georgetown City Hall |
| Old Main, Western Washington State College |
| Old North Yakima Historic District |
| Olsen, Ben, House |
| Olson, Louis and Ellen, House |
| Olympia Downtown Historic District |
| Olympia National Bank |
| Olympic Club Saloon |
| Olympic Hotel |
| Olympic National Park Headquarters Historic District |
| Olympus Guard Station |
| Opera House and I. O. O. F. Lodge |
| Orchard Terrace Apartments |
| Orient Bridge |
| Pacific Coast Company House No. 75 |
| Pacific County Courthouse |
| Pacific National Bank Building |
| Palmer, O. K., House |
| Panama Hotel |
| Pantages Theatre |
| Paradise Historic District |
| Paradise Inn |
| Paramount Theatre |
| Paris, Joseph, House |
| Park Butte Lookout |
| Patos Island Light Station |
| Patton Bridge |
| Peace Arch |
| Peaceful Valley Historic District |
| Pelton Creek Shelter |
| Pennsylvania Avenue-West Side Historic District |
| Penstock Bridge |
| Phillips, Dr. John and Viola, House and Office |
| Pickering Farm |
| Pike Place Public Market Historic District |
| Pioneer Building, Pergola, and Totem Pole |
| Pioneer Church |
| Pioneer Hall |
| Pioneer Square-Skid Road District |
| Pittock House |
| Point Robinson Light Station |
| Port Townsend Historic District |
| Powell House |
| Preston Hall |
| Pullman High School |
| Purdy Bridge |
| Purple Point-Stehekin Ranger Station House |
| Pyramid Peak Aircraft Warning Service Lookout |
| Pythian Temple |
| Queen Anne High School |
| Queen Anne Public School |
| Rainier Club |
| Randle Ranger Station-Work Center |
| Ravenna-Cowen North Historic District |
| Ravenna Park Bridge |
| Raymond Theater |
| Rector Hotel |
| Redmond City Park |
| Red Shield Inn |
| RELIEF (lightship) |
| Review Building |
| Rhodes, Henry A. and Birdella, House |
| Rhodesleigh |
| Richards, T.G., and Company Store |
| Ritzville Carnegie Library |
| Ritzville High School |
| Ritzville Historic District |
| Riverside Avenue Historic District |
| Roanoke Park Historic District |
| Roche Harbor |
| Rock Cabin |
| Rock Island Railroad Bridge |
| Rockwood Historic District |
| Roffler, John, House |
| Rogers, John R., High School |
| Rosalia Railroad Bridge |
| Rosario |
| Rosebush House |
| Rosemary Inn |
| Roth, Lottie, Block |
Data from United States Park Service and Wikidata
