Washington - Criteria: A (event)
| Okanogan County Courthouse |
| Okanogan Project: Conconully Resevoir Dam |
| Old Capitol Building |
| Old City Hall |
| Old City Hall Historic District |
| Old Georgetown City Hall |
| Old Main, Western Washington State College |
| Old-Man-House Site (45KP2) |
| Old North Yakima Historic District |
| Olmstead Place State Park |
| Olson, Mary, Farm |
| 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 |
| Panama Hotel |
| Pangborn-Herndon Memorial Site |
| Pantages Theatre |
| Paradise Historic District |
| Paradise Inn |
| Paramount Theatre |
| Park Butte Lookout |
| Parson Smith Tree |
| Patos Island Light Station |
| Peace Arch |
| Peaceful Valley Historic District |
| Pelton Creek Shelter |
| Penstock Bridge |
| Perry Creek Shelter |
| Peyton Building and Peyton Annex |
| Pickering Farm |
| Pike Place Public Market Historic District |
| Pioneer Building, Pergola, and Totem Pole |
| Pioneer Church |
| Pioneer Square-Skid Road District |
| Point No Point Light Station |
| Point Robinson Light Station |
| Point Wilson Lighthouse |
| Pomeroy Farm |
| Port Gamble Historic District |
| Port Townsend Historic District |
| Preston Hall |
| Pullman High School |
| Purdy Bridge |
| Pyramid Peak Aircraft Warning Service Lookout |
| Pythian Temple |
| Queen Anne High School |
| Rainier Club |
| Randle Ranger Station-Work Center |
| Ravenna-Cowen North Historic District |
| Ravenna Park Bridge |
| Raymond Theater |
| Red Men Hall |
| Redmond City Park |
| Red Shield Inn |
| RELIEF (lightship) |
| Rialto Theater |
| 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 Island Railroad Bridge |
| Rockwood Historic District |
| Roose, Peter, Homestead |
| Rosalia Railroad Bridge |
| Rosario |
| Rosemary Inn |
| Ruby Theater |
| Rucker House |
| Sacajawea State Park |
| Saint Edward Seminary |
| Salvation Army Building |
| SAND MAN (Tug Boat) |
| San Juan Island National Historic Site |
| Schade Brewery |
| Schafer State Park |
| Schmitz Park Bridge |
| Sears, Joshua, Building |
| Seattle Art Museum |
| Seattle Chinatown Historic District |
| Seattle Municipal Light and Power Plant |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seivers Brothers Ranchhouse and Barn |
| Selleck Historic District |
| Seventh Street Theater |
Data from United States Park Service and Wikidata
