Montana - Criteria: C (architecture/engineering)
| Kelly's Camp Historic District |
| Kemna, Herman, House |
| Kennedy Building |
| Kent Dairy Round Barn |
| Kerr House |
| Ketterer, Emil, House |
| Kevin Depot |
| Kintla Lake Ranger Station |
| Kishenehn Ranger Station Historic District |
| Kiwanis Meeting Hall |
| Kleinschmidt, T. H., House |
| Kluge House |
| Knowles Building |
| Kohrs, William K., Free Memorial Library |
| Kolble House |
| Kootenai Creek Snowshoe Cabin |
| Kootenai Lodge Historic District |
| Kopriva, Francis, House |
| Kose Hall |
| KPRK Radio |
| Krohne Island House |
| Krohne Spring House |
| Krug, Charles, House |
| Lagerquist, John, House |
| Lake McDonald Lodge |
| Lake McDonald Lodge Coffee Shop |
| Lake McDonald Lodge Historic District |
| Lancaster House |
| L and L Building |
| Landram, John A., House |
| LaPierre Barn |
| Larsen, Aage and Kristine, Homestead |
| Laurel Downtown Historic District |
| Lee Creek Snowshoe Cabin |
| Leibig House |
| Lewis and Clark Bridge |
| Lewis and Clark Caverns Historic District |
| Lewis and Clark County Hospital Historic District |
| Lewis, Samuel, House |
| Lewistown Carnegie Library |
| Lewistown Central Business Historic District |
| Lewistown Courthouse Historic District |
| Lewistown Merchantile Company |
| Lewistown Silk Stocking District |
| Libby High School |
| Lincoln Community Hall |
| Lincoln Creek Snowshoe Cabin |
| Lincoln Lodge |
| Lincoln School |
| Linderman, Frank Bird, House |
| Little Bear School |
| Little Blackfoot River Bridge |
| Locate Creek Bridge |
| Lockhart, Caroline, Ranch |
| Lockridge Medical Clinic |
| Lodge Grass Merchandise Company Store |
| Logan Creek Patrol Cabin |
| Logan Pass Visitor Center |
| Logging Creek Ranger Station Historic District |
| Lohman Block |
| Loneman Fire Lookout |
| Long House |
| Lorraine Apartments |
| Lost Horse Fireman's Cabin (24RA197) |
| Lower Bridger School |
| Lower Logging Lake Snowshoe Cabin and Boathouse |
| Lower Nyack Snowshoe Cabin |
| Lower Park Creek Patrol Cabin |
| Lucy Building |
| Lundwall, Charles, Building |
| Madison Hotel and Cafe |
| Main Street Historic District |
| Malmborg School |
| Many Glacier Barn and Bunkhouse |
| Many Glacier Campground Camptender's Cabin |
| Many Glacier Hotel Historic District |
| Marcus, Dr. Carl, House |
| Marcyes, Claude O., House |
| Margaret Block |
| Marias River Bridge |
| Marsh and Powell Funeral Home |
| Masonic Building |
| Masonic Lodge |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Matheson, Duncan, House |
| May, Albert, House |
| May, Charles, House |
| May, George, House |
| May, Harry, House |
| May, Louis, House |
| McCall, Tracy, House |
| McCart Fire Lookout |
| McFarlane House |
| McGee House |
| McGlauflin House |
| McMannamy House and Rental Properties |
| McMullen Hall |
| Meadowbrook Stock Farm |
Data from United States Park Service and Wikidata
