Ohio - Area of significance: Architecture
| Kent, Charles House |
| Kent Industrial District |
| Kent Jail |
| Kent, J., Residence |
| Kenton Courthouse Square Historic District |
| Kenton-Hunt Farm |
| Kenton Public Library |
| Kent, Zeno, House |
| Kenyon College |
| Kern, Rufus A., House |
| Kerr, Benjamin F., House |
| Kestler Building |
| Keyt, Gideon, House |
| Kies, Lewis, House |
| Kilbourn Commercial Building |
| Kilpi Hall |
| Kimball, Addison, House |
| Kimball House |
| Kimball, Lemuel II, House |
| Kindleberger, Frederick, Stone House and Barn |
| Kindra, W. H., Apartments |
| King, Ahimaaz, House |
| King, Dr., House |
| King-Phillips-Deibel House |
| King, William, House |
| Kingwood Center |
| Kinney, Eli, House |
| Kinney, James, Farmstead |
| Kirby, Josiah, House |
| Kirby Road School |
| Kirkwood, Joseph, House |
| Kirtland, Jared P., House |
| Kirtland Temple |
| Kiser Mansion |
| Kishman Fish Company Buildings |
| Kittinger, David, Residence |
| Klaus Block |
| Knapp, William, House |
| Knights of Columbus Building |
| Knowlton, Dr. William A., House |
| Knox County Courthouse |
| Knox County Infirmary |
| Koehne-Poast Farm |
| Kokosing House |
| Krause, John, House |
| Kress Building |
| Krippendorf-Dittman Company |
| Krippendorf Estate |
| Kroger Barnes Graf, Gretchen, House |
| Krug House |
| Krumberg, Theodore, Building |
| Krumm House |
| Kuebeler, August, House |
| Kuebeler-Stang Block |
| Kuenzer, Joseph II, House |
| Kuhns, Benjamin F., Building |
| Kulas, E. J., Estate Historic District |
| Kumler, Elias, House |
| Kunkle Log House |
| Labold House and Gardens |
| Lafayette Lodge No. 79 |
| Lafee Building |
| Lagonda Club Building |
| Laird Hall |
| Lakefork School |
| Lake Shore and Michigan Southern (LS&MS) Railroad Depot-Wauseon |
| Lake Shore And Michigan Southern Passenger Depot |
| Lake Shore And Michigan Southern Railroad Depot |
| Lake Shore and Michigan Southern RR Depot and Freight House |
| Lake Shore Bank and Cleveland Public Library St. Clair Branch |
| Lake Shore & Michigan Southern Railroad Station |
| Lakeside Historic District |
| Lake Township School |
| Lakewood Downtown Historic District |
| Lamberson-Markley Houses |
| Lambert-Parent House |
| Lancaster Historic District |
| Lancaster Methodist Episcopal Camp Ground Historic District |
| Lancaster West Main Street Historic District |
| Landes, Samuel, House |
| Landt Building |
| Lane, Ebenezer, House |
| Lane-Hooven House |
| Langdon House |
| Lanman-Ingram House |
| Lanning, T., & Co. Department Store |
| Lanterman Mill |
| Lasalle, Koch and Company Department Store |
| LaSalle Theater Building |
| Lash, William D., House |
| La Tosca Flats |
| Latty, Judge Alexander, House |
| Laughlin, Homer, House |
| Laundon, Thomas W., House |
| Laurel Homes Historic District |
| La Ventura Apartments |
| Lavin, Carl and Audrey, House |
| Lawndale Farm Complex |
| Layman, Christopher C., Law Office |
| Lay, Samuel, House |
Data from United States Park Service and Wikidata
