Washington - Area of significance: Architecture
| High Bridge Ranger Station Historic District |
| High Bridge Shelter |
| Highland Apartments |
| Hill-Hilscher House |
| Hill, Samuel, House |
| Hillside Historic District |
| Hjertoos, Andrew and Bergette, Farm |
| Hodgdon, Judge Charles W., House |
| Hoge Building |
| Holley-Mason Building |
| Holy Cross Polish National Catholic Church |
| Holyoke Building |
| Holy Trinity Episcopal Church |
| Holy Trinity Orthodox Church |
| Hoogdal School |
| Hoquiam Olympic Stadium |
| Hoquiam's Castle |
| Horan, Michael, House |
| Hotel Collins |
| Hotel Laube |
| Hotel Morck |
| Hotel Sorrento |
| Hotel Upton |
| House at 1510 Tacoma Avenue South |
| House at 1610 South G Street |
| House at 1723 Holcomb Street |
| House at 2314 South Ainsworth Avenue |
| House at 2326 South L Street |
| House at 30 Tremont Street |
| House at 503 Fir Street |
| House at 605 South G Street |
| House at 708-710 South 8th Street |
| House at 802-804 South G Street |
| House of Providence |
| Hovander Homestead |
| Howard, A. E., House |
| Howay-Dykstra House |
| Hubbard Bungalow |
| Huckleberry Creek Patrol Cabin |
| Hulbert, Edward & Laura, House |
| Hull Building |
| Humes Ranch Cabin |
| Hutton Building |
| Hutton, Levi and May Arkwright, House |
| Hutton Settlement |
| Hyak Shelter |
| Hyde, Samuel, House |
| Hyer, John A., Farm |
| Immanuel Lutheran Church |
| Independent Order of Odd Fellows (IOOF) Hall No. 148 |
| Indian Bar Trail Shelter |
| Indian Henry's Patrol Cabin |
| Indian Shaker Church |
| Interlake Public School |
| Interrorem Guard Station-Olympic National Forest |
| Ipsut Creek Patrol Cabin |
| Iron Pergola |
| Israel, Grover J., House |
| Issaquah Sportsmen's Club |
| Jaaska House and Warehouse |
| Jackson Hall Memorial Community Hall |
| Jefferson County Courthouse |
| Jeffers Studio |
| JOHN N. COBB (fisheries research vessel) |
| Johnson House |
| Johnson House |
| Jovita Land Company Model Home-Corbett House |
| Keewaydin Clubhouse |
| Keller House |
| Kelley, Mancel, House |
| Kemp & Hebert Building |
| Kiesow-Gentsch House |
| Kiggins, John P. and Mary, House |
| Kiggins Theater |
| Kirk, Lilly, House |
| Kirkman House |
| Kirk, Peter, Building |
| Kittitas County Fairgrounds |
| Klickitat County Courthouse |
| Knickerbocker |
| Knight House |
| Knights of Columbus Hall - Council No. 676 |
| Knuppenburg, James, House |
| Koerner House |
| Koma Kulshan Ranger Station |
| Kraus, Joseph, House |
| Kristoferson Dairy |
| Krumdiack Homestead |
| La Conner Historic District |
| LaFramboise Farmstead |
| Lake George Patrol Cabin |
| Lake-Little House |
| Lake Quinault Lodge |
| Lake Wenatchee Residence No. 1200 |
| LA MERCED |
| Lancaster, Judge Columbia, House |
| Landes, Colonel Henry, House |
| Larrabee House |
| Larson, A. E., Building |
| Larson-Hellieson House |
Data from United States Park Service and Wikidata
