Washington - Area of significance: Architecture
| Richey, James, House |
| Ridpath Hotel |
| Ritzville Carnegie Library |
| Ritzville High School |
| Ritzville Historic District |
| Riverside Avenue Historic District |
| Roanoke Park Historic District |
| Robinwood Aparments |
| Roche Harbor |
| Rock Cabin |
| Rockwood Historic District |
| Roeder, Victor A., House |
| Roffler, John, House |
| Rogers, John R., High School |
| Roosevelt Apartments |
| Roosevelt Hall |
| Rosario |
| Rosebush House |
| Rosedell |
| Rosemary Inn |
| Roslyn Historic District |
| Roth, Lottie, Block |
| Rothschild House |
| Rover, Hanna, House |
| Rucker Hill Historic District |
| Rucker House |
| Rudkin, Frank, House |
| Russell House |
| Rust, William Ross, House |
| Sacajawea State Park |
| Saint Edward Seminary |
| Salsich Lumber Company Superintendent's House |
| Salvation Army Building |
| Sandberg-Schoenfeld Buildings |
| Sanders, Erick Gustave, Mansion |
| Sanitary Meat Market |
| San Juan County Courthouse |
| San Marco |
| Saunders, James C., House |
| Sawyer, W. P., House And Orchard |
| Schade Brewery |
| Schafer State Park |
| Schlager, Ferdinand, House |
| Schmidt, Christian, House |
| Schmidt, F. W., House |
| Schmidt, Trueman and Virginia, House |
| SCHOONER MARTHA |
| Schulderman, Peter, House |
| Schultz Apartments |
| Schumann Building |
| Scout Lodge |
| Sears, Roebuck Department Store |
| Seattle Art Museum |
| Seattle Chinatown Historic District |
| Seattle Naval Hospital Chapel |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seehorn-Lang Building |
| Sehome Hill Historic District |
| Seivers Brothers Ranchhouse and Barn |
| Sekiu School |
| Seligman, William O. and Stella M., House |
| Semar Block |
| Seventh Street Theater |
| Sevier and Weed Building |
| Shafer Building |
| Sharp, James, House |
| Shawnee House |
| Shelbanks |
| Shelton Public Library and Town Hall |
| Shibles, Capt. Peter, House |
| Shobert, William Henry, House |
| Shogren Cottage |
| Shoudy House |
| Shuey, Henry Owen, House |
| Sigma Kappa Mu Chapter House |
| Silver Creek Ranger Station |
| Singer's Lake Crescent Tavern |
| Si View Park |
| Skagit River and Newhalem Creek Hydroelectric Projects |
| Skansie, Andrew & Bertha, Net Shed and House |
| Skinner Building |
| Skykomish Historic Commercial District |
| Slagle, Jesse W. & Elizabeth, House |
| Slocum House |
| Small-Elliott House |
| Smith, Edwin A., House |
| Smith, Nat, House |
| Smith, Peter, Farm-Donation Land Claim |
| Snohomish County Courthouse |
| Snohomish Historic District |
| Snoqualmie Depot |
| Solby, William and Margaret, House |
| Sole, Tollef, House |
| Sorenson House |
| Sourdough Mountain Lookout |
Data from United States Park Service and Wikidata
