Idaho - Criteria: C (architecture/engineering)
| Idaho State Forester's Building |
| Idaho State Industrial School Women's Dormitory |
| Idaho State Sanitarium Administration Building |
| Idaho State University Administration Building |
| Idaho State University Neighborhood Historic District |
| Idanha Hotel |
| Immanuel Evangelical Lutheran Church |
| Immanuel Methodist Episcopal Church |
| Independent Order of Odd Fellows Hall |
| Indian Springs School II |
| Innes, Kate, House |
| Intermountain Institute |
| Iona Meetinghouse |
| I.O.O.F. Building |
| I.O.O.F. Hall |
| Jackson, Orville and Floy, House |
| Jacobs, Cyrus, House |
| Jacobsen, N. A., Building |
| Jacobsen, N.A., House |
| J.C. Penney Company Building |
| JEAN (steamboat) |
| Jefferson County Courthouse |
| Jefferson, W. E., House |
| Jerome City Pump House |
| Jerome Cooperative Creamery |
| Jerome County Courthouse |
| Jerome First Baptist Church |
| Jerome National Bank |
| Johnson, Edgar, House |
| Johnson, J. M., House |
| Johnson, Louis, Water Tank House |
| Jones, Jedd, House |
| Jones, T. J., Apartments |
| Kappa Sigma Fraternity, Gamma Theta Chapter |
| Kehrer, Thomas J., House |
| Keller House and Derick |
| Kelley, Marion and Julia, House |
| Kelly's Hotel |
| Kelsey, Robert, Bungalow |
| Ketchum Ranger District Administrative Site |
| Kieldson Double House |
| Kinney, Joseph, Mausoleum |
| Kirby, Thomas, House |
| Knights of Pythias Lodge Hall |
| Kohl, W. S., Barn |
| Kootenai County Courthouse |
| Kootenai Inn |
| Korvola, John, Homestead |
| Krassel Ranger Station |
| Kress Building |
| Kunze, Rudolf, Barn |
| Kurtz-Van Sicklin House |
| KwikCurb Diner |
| Laine, James H., Barn |
| Laituri, Gust, Homestead |
| Largilliere, Edgar Walter, Sr., House |
| Larsen, Archie, House |
| Latham Bungalow |
| Laughlin, Ben, Water Tank House-Garage |
| Lava High School Gymnasium |
| Lawshe, George, Well House |
| LDS Seminary |
| LDS Stake Office Building |
| L.D.S. Ward Building |
| Lee, J.O., Honey House |
| Lee, J. O., House |
| Lemhi County Courthouse |
| Lemmon Hardware Store |
| Lewiston City Hall |
| Lewiston Depot |
| Lewiston Methodist Church |
| Lieuallen, Almon Asbury, House |
| Lincoln School |
| Little, Thomas K., House |
| Lochsa Historical Ranger Station |
| Lockman, Jacob P. House |
| Longfellow School |
| Long Valley Finnish Church |
| Lowell School |
| Lower Main Street Commercial Historic District |
| Lower Salmon River Archeological District |
| Low, Morris, Bungalow |
| Mackay Episcopal Church |
| Mackay Methodist Episcopal Church |
| MacMillan Chapel |
| Madison County Courthouse |
| Malad Second Ward Tabernacle |
| Mallard Peak Lookout |
| Mandl, Joseph, House |
| Map Rock Petroglyphs Historic District |
| Marks, M. J., House |
| Maxwell, Art and Frieda, Barn |
| McBeth, Sue, Cabin |
| McCammon State Bank Building |
| McCarthy, Judge Charles P., House |
| McCollum, Robert, House |
| McConnell-McGuire Building |
| McConnell, W. J., House |
| McElroy, H. E., House |
| McGinnis, J. S., Building |
Data from United States Park Service and Wikidata
