Washington - Significance region: Local
| San Juan Lime Company-Cowell's |
| San Marco |
| Sara Store |
| Saturno-Breen Truck Garden |
| Saunders, James C., House |
| Schade Brewery |
| Schlager, Ferdinand, House |
| Schmidt, Christian, House |
| Schmidt, F. W., House |
| Schmidt, Trueman and Virginia, House |
| Schulderman, Peter, House |
| Schultz Apartments |
| Schumann Building |
| Scout Lodge |
| Seal Rock Shell Mounds (45JE15) |
| Sears, Joshua, Building |
| Sears, Roebuck Department Store |
| Seattle Art Museum |
| Seattle, Chief of the Suquamish, Statue |
| Seattle Municipal Light and Power Plant |
| Seattle Naval Hospital Chapel |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Public Library |
| Seattle Yacht Club-Main Station |
| Seehorn-Lang Building |
| Sehome Hill Historic District |
| Sekiu School |
| Seligman, William O. and Stella M., House |
| Selleck Historic District |
| Semar Block |
| Sequim Opera House |
| 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 |
| Simpson Logging Company Locomotive No. 7 and Peninsular Railway Caboose No. 700 |
| Singer's Lake Crescent Tavern |
| Site 45-IS-2 |
| Si View Park |
| Skagit City School |
| Skansie, Andrew & Bertha, Net Shed and House |
| Skykomish Historic Commercial District |
| Slagle, Jesse W. & Elizabeth, House |
| Slip Point Light Station |
| Smith, Edwin A., House |
| Smith Hospital and Douglas County Press Building |
| Smith, Nat, House |
| Smith, Peter, Farm-Donation Land Claim |
| Snoqualmie Falls |
| Snoqualmie School Campus |
| Solby, William and Margaret, House |
| Sole, Tollef, House |
| Sorenson House |
| Sourdough Mountain Lookout |
| South Bend Carnegie Public Library |
| South Capitol Neighborhood Historic District |
| South Hill Historic District |
| South Side Historic District |
| Spokane City Hall Building |
| Spokane Club Building-Legion Building |
| Spokane County Courthouse |
| Spokane Fire Station No. 3 |
| Spokane Flour Mill |
| Spokane Public Library |
| Spokane Public Library |
| Spokane Public Library |
| Spokane Public Library |
| Spokane River Bridge at Long Lake Dam |
| Spokane Sash and Door Company Flats |
| Sprague Building |
| Springfield Farm |
| St. Andrew's Episcopal Church |
| St. Andrews Episcopal Church |
| Stanger, John, House |
| St. Anne's Roman Catholic Church |
| Stanwood IOOF Public Hall |
| Starrett House |
| Star Route and Palouse Street Brick Road |
| St. Boniface Church, Convent and Rectory |
| Steele, Alden Hatch, House |
| Steen, Helmer and Selma, House |
| Stegerwald, Andrew, House |
| Steilacoom Catholic Church |
| Steinke, Max, Barn |
| Steliko Ranger Station |
| Stella Blacksmith Shop |
| Stevens Pass Guard Station |
Data from United States Park Service and Wikidata
