Washington - Area of significance: Exploration/Settlement
| Shoudy House |
| Skagit City School |
| Small-Elliott House |
| Smith, Hiram F., Orchard |
| Smith, Peter, Farm-Donation Land Claim |
| Sole, Tollef, House |
| Southern Columbia Plateau and Okanogan Highlands Site No. 45DO1235 |
| Southern Columbia Plateau and Okanogan Highlands Site No. 45DO1243 |
| Southern Columbia Plateau and Okanogan Highlands Site No. 45DO1244 |
| Springfield Farm |
| Stanger, John, House |
| St. Boniface Church, Convent and Rectory |
| Steilacoom Historic District |
| St. Joseph's Mission |
| St. Paul's Mission |
| Swalwell Cottage |
| Swanson, Hans, House |
| Tharald Homestead |
| Thorp Mill |
| Tumwater Historic District |
| Tumwater Methodist Church |
| Underwood, Edward and Isabelle, Farm-Five Oaks Farm |
| Union Cemetery-Pioneer Calvary Cemetery |
| USS HORNET |
| Vancouver National Historic Reserve Historic District |
| Waitsburg Historic District |
| Waring, Guy, Cabin |
| Washington Hotel |
| Whitcomb Cabin |
| Whitman Mission National Historic Site |
| Wild Goose Pass Tree |
| Yama & Nagaya Village |
Data from United States Park Service and Wikidata
