Washington - Area of significance: Architecture
| Mickelson, Ole, Cabin |
| Midway School |
| Miller, Alexander, House |
| Miller Block |
| Miller, George, House |
| Miller, John J., House |
| Millersylvania State Park |
| Mill House |
| Millionaire’s Row Historic District |
| Mills Building |
| Millwood Historic District |
| Mineau, Francis, House |
| Mineral Log Lodge |
| Miners Ridge Lookout |
| Minkler, Birdsey D., House |
| Mission Avenue Historic District |
| Monroe Street Bridge |
| Montague and McHugh Building |
| Monte Cristo Hotel |
| Montlake Historic District |
| Montvale Block |
| Moore, Edward B., House |
| Moore, Miles C., House |
| Moore Theatre and Hotel |
| Moran State Park |
| Morgan, O. L. and Josephine, House |
| Morse Hardware Company Building |
| Morse House |
| Morse, Robert I., House |
| Mount Baker Park Historic District |
| Mount Baker Park Improvement Club Clubhouse |
| Mount Baker Theatre |
| Mount Rainier National Park |
| Mount Saint Michael |
| Mount Spokane Vista House |
| Mount Zion Baptist Church |
| Mowich Lake Patrol Cabin |
| Mukilteo Light Station |
| Munson, Herbert and Barbara House |
| Murray, Frederick H., House |
| Muzzy-Shine House |
| MV KALAKALA (ferry) |
| MV WESTWARD (Wooden Motor Vessel) |
| Narada Falls Bridge |
| Narada Falls Comfort Station |
| National Bank of Tacoma |
| National Guard Armory - Olympia |
| Naval Air Station (NAS) Seattle |
| Naval Auxiliary Air Station-Arlington |
| Naval Lodge Elks Building |
| Naval Military Hangar-University Shell House |
| Naval Reserve Armory |
| Neely, Sr., Aaron and Sarah, Farm |
| Neighbor-Bennett House |
| Nelson, Albert, Farmstead |
| Nelson, Charles F., House |
| Nelson House |
| Nelson-Parker House |
| Nettleton's Addition Historic District |
| Newell, Charles, House |
| New Richmond Hotel |
| New Washington Hotel |
| Nifty Theatre |
| Nilsson, Andrew, House |
| Ninth Avenue Historic District |
| Nisqually Entrance Historic District |
| Nisqually Power Substation |
| North Bend Ranger Station |
| North Coast Casket Company Building |
| North Creek School |
| Northern Bank and Trust Building |
| Northern Life Tower |
| Northern State Hospital |
| North Fork Guard Station No. 1142 |
| North Fork Quinault Ranger Station |
| North Fork Sol Duc Shelter |
| North Mowich Trail Shelter |
| Northrop Primary School |
| North Slope Historic District |
| Nuclear Reactor Building |
| Oatman, Earl, House |
| Officers Row, Fort Vancouver Barracks |
| Ohanapecosh Comfort Station No. O-302 |
| Ohanapecosh Comfort Station No. O-303 |
| Okanogan County Courthouse |
| Old City Hall |
| Old City Hall Historic District |
| Old Georgetown City Hall |
| Old German Consulate |
| Old Indian Agency |
| Old Main |
| Old Main, Western Washington State College |
| Old North Yakima Historic District |
| Old Public Safety Building |
| Olsen, Ben, House |
| Olson, Louis and Ellen, House |
| Olson, Mary, Farm |
| Olympia Downtown Historic District |
| Olympia National Bank |
| Olympia Public Library |
Data from United States Park Service and Wikidata
