Iowa - Significance region: Local
| Hancock, Charles T., House |
| Hancock County Courthouse |
| Hansen, Andrew P., Farmstead |
| Hanson, Alfred, House |
| Harbach, L. and Sons Furniture Warehouse and Factory Complex |
| Hardacre Theater |
| Hardin County Courthouse |
| Hardin County Home Historic District |
| Hardware Building |
| Harker House |
| Harlan Courthouse Square Commercial District |
| Harlan House Hotel |
| Harmon and LeValley Northwest Historic District |
| Harper and McIntire Company Warehouse |
| Harriman, Dr. O. B., House |
| Harris, Dr. Percy and Lileah, House |
| Harrison County Courthouse |
| Harrison, E. H., House |
| Harris Wagon and Carriage Shop |
| Harvat, Emma J., and Mary E. Stach House |
| Hatton, Dr. John B. and Anna M., House |
| Hauschild's Hall |
| Hawarden City Hall, Fire Station and Auditorium |
| Hawkeye Insurance Company Building |
| Hawkeye Transfer Company Warehouse |
| Hawthorne Glove and Novelty Company-Shrader Drug Company Building |
| Hayesville Independent School |
| Hayes, William B., House |
| Haymarket Commercial Historic District |
| Hays, E. R., House |
| Hazen, Allen, Water Tower |
| Hebard, Alfred, House |
| Hebert, Louis, House |
| Hedge Block |
| Heinz, Bonaventura, House (second) |
| Helvig-Olson Farm Historic District |
| Henderson, Daniel and Nancy Swaford, House |
| Henne, Robert, House |
| Henry County Courthouse |
| Henry County Savings Bank |
| Henryson, Henry T. and Emilie (Wiese), House |
| Henshie-Briggs Row House |
| Henyon-Kasper-Duffy Barn |
| Heritage Hill Historic District |
| Herndon Hall |
| Herring Hotel |
| Herring Motor Car Company Building |
| Herschel-Spillman Two-Row Portable Menagerie Carousel |
| Herschler, Christian and Katharina, House, Barn and Outbuildings Historic District |
| Hibernia Hall |
| Hickman-Nietert-Odd Fellows Building |
| Highland Historic District |
| Highland Park Historic Business District at Euclid and Sixth Avenues |
| Highlandville School |
| Highwater Rock |
| Hiller Building |
| Hillside |
| Hippee Building |
| Historic Railroad District |
| Hoag, J. J., House |
| Hobson Block |
| Hoersch, John, House |
| Hoffman Building |
| Hoffman, Phil, House |
| Hoffman, Samuel, Jr., House |
| Hofmann Building |
| Hohberger Building |
| Holbrook, William, House |
| Holland, Ora, House |
| Hollenfelz House |
| Holmes, John S. and Elizabeth Beem, Barn |
| Holy Ghost Catholic Historic District |
| Holy Guardian Angels Church and Cemetery Historic District |
| Holy Trinity Greek Orthodox Church |
| Home of Marshall's Horseradish |
| Home Oil Service Station |
| Honey Creek Friends' Meetinghouse |
| Hoosier Row School |
| Hope Fire Company Engine House |
| Hornback, Emily, House |
| Horn House |
| Horton-Suiter House |
| Hose Station No. 1 |
| Hose Station No. 6 |
| Hose Station No. 7 |
| Hotel Burlington |
| Hotel Charitone |
| Hotel Chieftain |
| Hotel Fort Des Moines |
| Hotel Greenfield |
| Hotel Hurst |
| Hotel Hurst Garage |
| Hotel Iowa |
| Hotel Kirkwood |
| Hotel Lester-Lester Cafe |
| Hotel Manning |
| Hotel Mealey |
| Hotel Mississippi-RKO Orpheum Theater |
| Hotel Ottumwa |
| Hotel President |
Data from United States Park Service and Wikidata
