Montana - Area of significance: Architecture
| Hospital |
| Hotel Baxter |
| Hotel Metlen |
| Hough, Raymond, House |
| House at 112 Park Street |
| House at 22 West Lamme |
| House at 301 Eighth Avenue, South |
| House at 324 W. Corcoran |
| House at 618 West Janeaux |
| House at 714 North Tracy |
| House at 805 W. Watson |
| House at 809 W. Watson |
| House at 813 W. Watson |
| House at 818 South Eighth |
| House at 916 Preston Avenue |
| House of the Good Shepherd Historic District |
| House on Railroad Avenue |
| Houtz House |
| Howard Lepper Memorial Hall |
| Howe, John G., House |
| Howes' Lake McDonald Cottage Sites Historic District |
| Hoyt House |
| Huckleberry Fire Outlook |
| Huntoon Residence |
| Huseby, John H,. House |
| Independent Telephone Company Building |
| Ingomar Public School |
| IOOF Hall |
| IOOF Hall and Fromberg Co-operative Mercantile Building |
| IOOF Lodge |
| Ismay Jail |
| Jacobs, Michael, House |
| James F. Battin Federal Building (Courthouse & Federal Office Building) |
| Jefferson County Courthouse |
| Johnson House |
| Johnson-Lee House |
| Johnston, John S., House |
| Joliet Residential Historic District |
| Judith Landing Historic District |
| Judith Place Historic District |
| Judith River Ranger Station |
| Kalispell-American Laundry |
| Kalispell Flour Mill |
| Kalispell Main Street Historic District |
| Kate Fratt Memorial Parochial School |
| Kearney Rapids Bridge |
| Keith, Harry C., House |
| Keith, John M., House |
| 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 |
| Kraftenberg Homestead |
| Krohne Island House |
| Krohne Spring House |
| Krug, Charles, House |
| Kruse, Billy, Cabin |
| Lagerquist, John, House |
| Laird's Lodge Historic District |
| 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 |
| Lavina School Historic District |
| Lee Creek Snowshoe Cabin |
| Leibig House |
| Lewis and Clark Caverns Historic District |
| Lewis and Clark County Hospital Historic District |
| Lewis-Nevala Homestead |
| 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 |
Data from United States Park Service and Wikidata
