All - Constructed - 1870–1879
| Judd, Thomas, House |
| Kable House |
| Kalmia Club, The |
| Kane, Thomas L., Memorial Chapel |
| Kanosh Tithing Office |
| Karnes Stone Barn |
| Kauffman, Linus B., House |
| Kaufman-Straus Building |
| Keck Homestead |
| Kehukee Primative Baptist Church |
| Kelley, Mercelia Evelyn Eldridge, House |
| Kemper Hall |
| Kendall, Silas W., House |
| Kewaunee County Sheriff's Residence and Jail |
| Keyser-Cullen House |
| King Philip Mills |
| Kitty Hawk Life-Saving Station |
| Knight, R. A.-Eugene Lacount House |
| Knight's Foundry and Shops |
| Knightstown Academy |
| Knox County Courthouse |
| Knoxville College Historic District |
| Koenig Building |
| Koester, Charles, House |
| Kosciusko County Jail |
| Kuehn, Lucas, House |
| Lachmund Family House |
| La Cueva Historic District |
| Ladies Library Association Building |
| Lafayette County Courthouse |
| Lancaster Covered Bridge |
| Lander's Wagon and Carriage Shop |
| Landrum, Andrew J., House |
| Lanneau-Norwood House |
| Lanphere-Pratt House |
| Lansburgh, Julius, Furniture Co., Inc. |
| LaPrairie Grange Hall No. 79 |
| Larrabee's Brick Block |
| Larson, L. A., & Co. Store |
| Laughlin, James H. and Frances E., House |
| Laureano Cordova Mill |
| La Veta Pass Narrow Gauge Railroad Depot |
| Lawrence and Chapin Building |
| Lawrence Model Lodging Houses |
| Lawrence Public School |
| Lawton, C. A., Company |
| Lead Historic District |
| Ledet House |
| Lee, John and Rosetta, House |
| Lefler-Woodman Building |
| Le Mars Public Library |
| Leuty, Isaac, House |
| Lewellyn, John T., House |
| Lewis House |
| Lewis, John C. and Augusta (Covell), House |
| Lewis-Syford House |
| Lighthouse |
| Lilienfeld, David, House |
| Lilly, Augustus, House |
| Lincoln Tomb |
| Lindsley House |
| Linwood Plantation Manager's House |
| Liston Range Rear Light Station |
| Little Bighorn Battlefield National Monument |
| Little Loomhouses |
| Little Sable Point Light Station |
| Little Silver Station |
| Livingstone College Historic District |
| Llenroc |
| Locke-Ober Restaurant |
| Locust Creek Covered Bridge |
| Logan County Courthouse |
| Lone Star School, District 64 |
| Lone Tree School |
| Loreto Shrine Chapel |
| Lovejoy, A. L., House |
| Lower Animas Ditch |
| Ludington House |
| Ludington North Breakwater Light |
| Ludlow Graded School |
| Luther Place Memorial Church |
| Lyman Viaduct |
| Lyons, Oscar F., House |
| Mackie Building |
| Madison Atchison, Topeka and Santa Fe Railroad Depot |
| Madrona Knoll Rancho District |
| Main Road |
| Malcolm X-Ella Little Collins House |
| Mammoth Historic District |
| Manistee North Pier |
| Manning, Jacob, House |
| Manning, Joseph K., House |
| Mansion House Hotel |
| Marchetti, Louis, House |
| Marentis House |
| Mariah's Chapel |
| Marindahl Post Office |
| Marion Catholic School |
| Marshall's Store |
| Martinez, Gilbert, Barn |
Data from United States Park Service and Wikidata
