Connecticut - Criteria: C (architecture/engineering)
| Gwyn Careg |
| Haddam Center Historic District |
| Hadlyme Ferry Historic District |
| Hadlyme North Historic District |
| Hait, Benjamin, House |
| Hale, Dr. Elizur, House |
| Hale, Nathan, Homestead |
| Hall-Benedict Drug Company Building |
| Hall, Isaac Davis and Marion Dalton, House |
| Hallville Mill Historic District |
| Halpine, J. S., Tobacco Warehouse |
| Hamburg Bridge Historic District |
| Hamden Bank & Trust Building |
| Hamden High School |
| Hamden Memorial Town Hall |
| Hamilton Park |
| Hammanasset Paper Mill Site |
| Hampton Hill Historic District |
| Hampton Inn |
| Harris, Jonathan Newton, House |
| Harrison, Thomas, House |
| Hartford Club |
| Hartford Colony |
| Hartford Electric Light Company Maple Avenue Sub-Station |
| Hartford Golf Club Historic District |
| Hartford National Bank and Trust |
| Hartford & New Haven Railroad Depot |
| Hartford & New Haven Railroad-Freight Depot |
| Hartford Seminary Foundation |
| Hartford Union Station |
| Hart, Gen. William, House |
| Hart's Corner Historic District |
| Hart, Timothy, House |
| Harvey, William H., House |
| Hastings Hill Historic District |
| Hathaways Store |
| Hatheway House |
| Hattertown Historic District |
| Haviland and Elizabeth Streets-Hanford Place Historic District |
| Hawley, Thomas, House |
| Hayden, Capt. Nathaniel, House |
| Hayes, Samuel II, House |
| Haystack Mountain Tower |
| Hayward House |
| Hazardville Historic District |
| Hazelton, James, House |
| Hearthstone |
| Hebrew Congregation of Woodmont |
| Hebron Center Historic District |
| Hemlock Glen Industrial Archeological District |
| Hempstead Historic District |
| Hempstead, Joshua, House |
| Hempsted, Nathaniel, House |
| Heublein Tower |
| Hibbard, Enoch, House and Grannis, George, House |
| Higganum Landing Historic District |
| Highland Historic District |
| High Street Historic District |
| Hillhouse Avenue Historic District |
| Hill's Academy |
| Hillside |
| Hillside Historic District |
| Hill-Stead |
| Hilltop Farm |
| Hine-Buckingham Farms |
| Hitchcock-Schwarzmann Mill |
| Hoadley, Isaac, House |
| Hoadley, John, House |
| Hoadley, Orrin, House |
| Hodges Square Historic District |
| Hodgson, Richard and Geraldine, House |
| Holabird House |
| Holcomb, Judah, House |
| Holcomb, Nathaniel, III, House |
| Hollister, Homestead, The |
| Hollister, John, House |
| Holmes, Francis H., House |
| Home Woolen Company |
| Hooker, Elizabeth R., House |
| Hooker, Henry, House |
| Hooker, John and Isabella, House |
| Hooker, Sarah Whitman, House |
| Hose and Hook and Ladder Truck Building |
| Hosmer, Daniel, House |
| Hotchkiss, David, House |
| Hotchkissville Historic District |
| Hotel America |
| Hotel Beach |
| Housatonic Railroad Station |
| Housatonic River Railroad Bridge |
| House at 1010 Shuttle Meadow Road |
| House at 111 Maple Avenue |
| House at 130 Hayden Station Road |
| House at 130 Mohegan Avenue |
| House at 140 and 144 Retreat Avenue |
| House at 161 Damascus Road |
| House at 29 Flat Rock Road |
| House at 36 Forest Street |
| House at 44 Court Street |
| House at 590 West Street |
Data from United States Park Service and Wikidata
