Washington - Area of significance: Architecture
| Larson, Lewis P., House |
| Latah School |
| Laubach, J. N., House |
| Laughlin Round Barn |
| La Wis Wis Guard Station No. 1165 |
| Leamington Hotel and Apartments |
| Leary, Eliza Ferry, House |
| Leavenworth National Fish Hatchery |
| Leavenworth Ranger Station |
| Leavenworth Ski Hill Historic District |
| Leonard, T. A., Barn |
| Lester Depot |
| Levesque-Majer House |
| Lewis & Clark High School |
| Lewis County Courthouse |
| Lewis, Hannah, House |
| Lewisville Park |
| Liberty Historic District |
| Liberty Theater |
| Liggett Building |
| Lincoln Hotel |
| Lincoln School |
| Lindsey, William, House |
| Littlebrook |
| Little Falls Hydroelectric Power Plant |
| Loers, Benjamin, House |
| Longbranch School Gymnasium |
| Longfellow Elementary School |
| Long Lake Hydroelectric Power Plant |
| Long Lake Recreation Hall |
| Longmire Buildings |
| Longmire Campground Comfort Station No. L-302 |
| Longmire Campground Comfort Station No. L-303 |
| Longmire Campground Comfort Station No. L-304 |
| Longmire Historic District |
| Long, Robert Alexander, High School |
| Longview Civic Center Historic District |
| Longview Community Church |
| Longview Community Church-Saint Helen's Addition |
| Longview Community Store |
| Longview Women's Clubhouse |
| Lord, C. J., Mansion |
| Lord-Heuston House |
| Lord, Richard Hinton, House |
| Lost Lake Guard Station |
| LOTUS (motor vessel) |
| Lotz, J. H., House |
| Lowe, David, House |
| Lucas Homestead |
| Lucerne Guard Station |
| Ludwigs, George, House |
| Luepke Florist |
| Lumber Exchange Building |
| Lund Building |
| Lutheran St. Paul's Kirche |
| Lynn, C.O., Co. Funeral Home |
| Lyon Building |
| Lytle, Joseph, Home |
| Magnolia Public Library |
| Malaney-O'Neill House |
| Manley-Thompson Ford Agency |
| Manresa Hall |
| Marcus Whitman Hotel |
| Marine Supply and Hardware Complex |
| Marsh, Louis S., House |
| Marycliff-Cliff Park Historic District |
| Maryhill |
| Mary Queen of Heaven Roman Catholic Church |
| Marysville Opera House |
| Mason County Courthouse |
| Masonic Hall |
| Masonic Hall- Port Orchard |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple-Auburn |
| Masonic Temple Building-Temple Theater |
| Masonic Temple-Hoquiam |
| Matzen, George and Irene, House |
| McAllister, Alexander, House |
| McAlmond House |
| McCabe Building |
| McCauley, H. M., House |
| McChord Field Historic District |
| McCleary, Henry, House |
| McCleary Hotel, Old |
| McCroskey, R. C., House |
| McFadden, O. B., House |
| McGrath Cafe and Hotel-The McGrath |
| McIlvaine Apartments |
| McKinley School |
| McMillen-Dyar House |
| McTaggert, Lachlin, House |
| Medical Dental Building |
| Meeker, Ezra, Mansion |
| Meese, Gustav, Building |
| Merrill, R. D., House |
| Metaline Falls School |
| Methodist Epscopal Church of Port Hadlock |
| Meyer House |
| Michael's Cabin |
Data from United States Park Service and Wikidata
