Ohio - Significance region: Local
| Hotel Rieger |
| Hotel Statler |
| House at 624 Washinton St. |
| House, Col. Erastus, House |
| House of Wills |
| House on Huron Ave. |
| Housley, R. A., House |
| Houston House |
| Howard, C. R., House |
| Howell and Anna Powell Farm |
| Hower Mansion |
| Howe Tavern |
| Hoyt Block |
| Hruby Conservatory of Music |
| Hubbard Cooke Block |
| Hubbard, Lester, House |
| Hubbard, S. B., House |
| Huber, Dr. H., Block |
| Hudson Avenue Historic District |
| Hueston, Matthew, House |
| Hueston Woods Park Mound |
| Huffman Historic District |
| Hughes School |
| Hulbert House and McAlpin Bridal Cottage |
| Hulburt, Halsey, Homestead |
| Hull, Isaac, Store |
| Hull, Jasper G., House |
| Hull, Patrick, House |
| Hull Place |
| Hull-Wolcott House |
| Humberger House |
| Hune, William, Farm |
| Hunter, James, Stone House |
| Hunter, William, House |
| Hunt-Forman Farm |
| Hunting Lodge Farm |
| Huntington, Franz, House |
| Huntington Grange |
| Huntington Inn, Old |
| Huntington, John, Pumping Tower |
| Huntington Public School |
| Huntington Township Hall |
| Hunts Corners |
| Hunt-Wilke Farm |
| Hurley Mound |
| Huron County Children's Home |
| Huron County Courthouse And Jail |
| Huron Harbor Light |
| Huron School |
| Huron-Superior Streets Warehouse-Produce Historic District |
| Hurst, William E., House |
| Hurth Hotel |
| Hyde Park Methodist Episcopal Church |
| Ida Street Viaduct |
| Iddings, Benjamin, Log House |
| Ideal Department Store Building |
| Idora Park |
| Ijams, Joseph, House |
| Ikirt House |
| Immaculate Conception Church |
| Immaculate Conception Church, School, and Rectory |
| Independence Presbyterian Church |
| Independent Order of Oddfellows, Dayton Lodge No. 273 |
| Independent Order of Odd Fellows Temple |
| Independent School District No. 2 Building |
| Indianola Junior High School |
| Indian Run Cemetery Stone Walls |
| Ingersoll, Cyrus J., House |
| Inglewood Historic District |
| Insco Apartments Building |
| Inter County Highway 360 |
| Interurban Bridge |
| Inverness Club |
| Ira Apartments |
| Ireland, Joseph, House |
| Irishtown Bend Archeological District |
| Isham, John, Farmstead |
| Isham, John, House |
| Island House |
| Iuka Ravine Historic District |
| Iutzi, Christian, Farm |
| Izant, Grace Goulder, House |
| Jackson, Andrew, House |
| Jackson Fort |
| Jackson Jr. High School |
| Jacob's Church |
| Jacobs, Felix A., House |
| Jaite Mill Historic District |
| James, Charles Worth, House |
| Jamestown Opera House |
| Jarvis House |
| Jeffers, H. P., Mound |
| Jefferson Avenue Historic District |
| Jefferson Schoolhouse |
| Jefferson Town Hall |
| Jeffrey Manufacturing Company Office Building |
| Jenkins-Perry House |
| Jennings Apartments |
| Jersey Independent Order of Odd Fellows Hall |
| Jewett, Frank, House |
Data from United States Park Service and Wikidata
