All - Architectural style - Italianate architecture
| Hoyt, Benjamin, House |
| Hubbardston Public Library |
| Hub Building |
| Huber, Dr. H., Block |
| Huddleston, Judge Killis, House |
| Huger, Cleland Kinloch and Burnet R. Maybank, House |
| Hughes, Langston, House |
| Hull House |
| Humphrey, Herman L., House |
| Hunter, Norvall, Farm |
| Hunt,Samuel, House |
| Hurst, William L., Law Office |
| Huson, Henry H., House and Water Tower |
| Hutchison, Joshua K., House |
| Hutto Commercial Historic District |
| Hydrant No. 3 House |
| Hyer's Hotel |
| Immaculate Conception Rectory at Botkins |
| Ingalsbe, Adolphus and Sarah, House |
| Inglewood |
| Inman I.O.O.F. Hall |
| IOOF Centennial Building |
| I.O.O.F. (International Order of Odd Fellows) Valley Junction Lodge Hall No. 604 |
| Iron Block |
| Island House |
| Jacobs Building |
| Jaffa Opera House |
| James, Jean Butz, Museum of the Highland Park Historical Society |
| James Pratt Funeral Service |
| Janin Store |
| Jasper County Courthouse |
| Jefferis, Thomas, House |
| Jefferson Fire Station |
| Jefferson Historic District |
| Jemison, Robert, Servants' House |
| Jemison School-Drish House |
| Jenkins, Joseph J., House |
| Jenks, Capt. Austin, House |
| Johnson, Abner C., House |
| Johnson, Alphonso, House |
| Johnson County Courthouse |
| Johnson, Franklin, House |
| Jonas, Karel, House |
| Jones, A.D. (Boss), House |
| Jones, David J. and Maggie, House |
| Jones, John, House |
| Jones-Read-Touvelle House |
| Jones, Tauy, House |
| Joseph-Cherrington House |
| Kapuaiwa Building |
| Kauffman, Linus B., House |
| Kelley, Barney, House |
| Kelley, Mercelia Evelyn Eldridge, House |
| Kelly, Amos, House |
| Kelsey, Porter, House |
| Kemp Barn |
| Kemper Hall |
| Kemp Place |
| Kendall County Courthouse |
| Kendall Manor |
| Kerr, John G., Company |
| Kewaunee County Sheriff's Residence and Jail |
| Keyes, Amos, House |
| King Block |
| Kington, W. W., House |
| Kinney, A., House |
| Kinney, James, Farmstead |
| Kirshbaum, Raphael, Building |
| Kixmiller's Store |
| Klondike Hotel |
| Knox County Courthouse |
| Knuessl Building |
| Kohler, John Michael, House |
| Kohlhagen Building |
| Krumberg, Theodore, Building |
| Krumm House |
| Kuehn, Lucas, House |
| Kurtz House |
| Lafayette County Courthouse |
| Lafayette Hardware Store |
| Lambert-Parent House |
| Lander's Wagon and Carriage Shop |
| L and L Building |
| Lane, Samuel M., House |
| Lane University |
| Lange Hotel |
| Lanphere-Pratt House |
| Lapham, Ambrose S., House |
| Lappin-Hayes Block |
| LaPrairie Grange Hall No. 79 |
| Larkin, Arthur, House |
| Larson, L. A., & Co. Store |
| Latto, Rudolph, House |
| Laue, Frederick, House |
| Lauerman Brothers Department Store |
| Laughlin, James H. and Frances E., House |
| Lawn, The |
| Lawrence, William, House |
| Lawton, C. A., Company |
| Layman, Christopher C., Law Office |
Data from United States Park Service and Wikidata
