Ohio - Significance region: Local
| Grand Army of the Republic Memorial Hall |
| Grand Lake St. Marys Lighthouse |
| Grand Pacific Hotel |
| Grant, A. G., Homestead |
| Grant Deming's Forest Hill Allotment Historic District |
| Grant-Deneau Tower |
| Graphic Arts Building |
| Gray-Coulton House |
| Great American Racing Derby |
| Great Lakes Historical Society Marine Museum |
| Great Mound |
| Great Southern Hotel and Theatre |
| Great Western Schoolhouse |
| Greek Revival Commercial Building |
| Greek Revival Farmhouse, Old |
| Greene Township Center |
| Greenfield Commercial Historic District |
| Green Island Light |
| Green Lawn Abbey |
| Green Lawn Cemetery |
| Greenlawn Cemetery Chapel |
| Green Plain Monthly Meetinghouse |
| Green Township High School |
| Greenville Mausoleum |
| Greenville South Broadway Commercial District |
| Greenwood Farm |
| Greenwood Farm |
| Gregg-Crites Octagon House |
| Gregg House |
| Gregory House |
| Greyhound Bus Station |
| Grieve, Martin and Louise, House |
| Griffin, A. B.,-O. H. Griffin House |
| Griffin, Alexander B., House |
| Griffith, James, House |
| Griggs Grange No. 1467 |
| Grinnell Mill Historic District |
| Griswold Memorial Young Women's Christian Association |
| Griswold, Peck, House |
| Groesbeck, Grace, House |
| Gross, L.N., Company Building |
| Grossman Paper Box Company |
| Groveport Log Houses |
| Groveport School |
| Groveport Town Hall Historic Group |
| Groveport United Methodist Church |
| Gruen Watch Company-Time Hill |
| Gummer House |
| Gunn House |
| Gurney-Kochheiser House |
| Hackenberg, Harvey, House |
| Haddon Hall |
| Haffey, Parley, Farm Complex |
| Haines, Frank, House |
| Haines House |
| Hale, Elijah, Residence |
| Hale, Jonathan, Homestead |
| Halle Building |
| Halle's Shaker Square |
| Hall Park Allotment Historic District |
| Hamilton Catholic High School |
| Hamilton Downtown Historic District |
| Hamilton, Gilbert H., House |
| Hamilton-Ickes House |
| Hamilton, J. L., Residence |
| Hamilton Park Historic District |
| Hamlet, The |
| Hancock and Dow Building |
| Hangar, The |
| Hanitch-Huffman House |
| Hanna House |
| Hanna-Kenty House |
| Hanson House |
| Hanson Machinery Company |
| Hardesty, Ralph, Stone House |
| Hardin County Courthouse |
| Harmon, Francis E., House |
| Harmony Hill Dairy House |
| Harp Apartments |
| Harper-Cosgrave Block |
| Harper, Rice, House |
| Harper, Samuel, Stone House |
| Harpersfield Covered Bridge |
| Harper, William Rainey, Log House |
| Harris, Franklin, Farmstead |
| Harrison-Landers House |
| Harrison National Bank |
| Harris, Stephen R., House |
| Harshey, John, Residence |
| Harshman, Charles, House |
| Hart, Edward, House |
| Hart, Gideon, House |
| Hartley Mound |
| Hart, Lucy, House |
| Hartman Hotel |
| Hartong, Levi J., House and Farm |
| Hart's Drug Store |
| Hartville Hotel |
| Harvard School |
| Harvey, Eli, House |
Data from United States Park Service and Wikidata
