Delaware - Significance region: Local
| Delaware Avenue Historic District |
| Delaware Trust Building |
| Delmarva Power and Light Building |
| Denny, T. H., House |
| Dickerson Potato House |
| Dingee, Jacob, House |
| Dingee, Obadiah, House |
| Dinker-Irvin Cottage |
| Dixon, S. P., Farm |
| Dodd Homestead |
| Dover Green Historic District |
| Downs, N. C., House |
| Downtown Harrington Historic District |
| Downtown Wilmington Commercial Historic District |
| Draper-Adkins House |
| Dupont, P. S., High School |
| Durham-Shores House |
| East Brandywine Historic District |
| Eastburn, Davis, Farm |
| Eastburn, J., Barn |
| Eastburn-Jeanes Lime Kilns Historic District |
| Eden Hill |
| Eighth Street Park Historic District |
| Eliason, A., House |
| Ellendale State Forest Picnic Facility |
| Elm Grange |
| Eratt House |
| Evans, George, House |
| Evans, John, House |
| Evans-West House |
| Exchange Building |
| Fairview |
| Fairview |
| Fairview |
| Faucett, Peter S., House |
| Fell Historic District |
| Felton Historic District |
| Felton Railroad Station |
| Fennimore Store |
| Ferguson, Robert, House |
| Ferris, Zachariah, House |
| Fields Heirs |
| First National Bank of Seaford |
| Fisher, Andrew, House |
| Fisher's Paradise |
| Fleming House |
| Foord & Massey Furniture Company Building |
| Frederica Historic District |
| Friends Meetinghouse |
| Galloway-Walker House |
| Garrett Snuff Mill |
| George Farmhouse |
| Georgetown Coal Gasification Plant |
| Godwin School |
| Golden Mine |
| Gordon, J. M., House |
| Govatos'/McVey Building |
| Grace United Methodist Church |
| Graham, Robert, House |
| Granite Mansion |
| Grantham-Edwards-McComb House |
| Gray, Charles, Printing Shop |
| Greenlawn |
| Green Mansion |
| Green Mansion House |
| Green Meadow |
| Griffith's Chapel |
| Grose, Robert, House |
| Gyles, Stella Pepper, House |
| Hart House |
| Hazel Glen |
| Hazzard House |
| Head of Christiana United Presbyterian Church |
| Hearn Potato House |
| Hebron Methodist Protestant Church and Cemetery |
| Hedgelawn |
| Hermitage, The |
| Hersey-Duncan House |
| Hicklen, William, House |
| Hickman Blacksmith Shop and House |
| Higgins, S., Farm |
| Hill Island Farm |
| Hill, Robert, House |
| Hitch, E. L., Potato House |
| Hockessin Friends Meetinghouse |
| Hoffecker-Lockwood House |
| Holladay-Harrington House |
| Holly Oak |
| Holton, S., Farm |
| Homestead Hall |
| Hopkins' Covered Bridge Farm |
| Howard High School |
| Hudson, Alfred L., House |
| Hughes-Willis Site |
| Idalia Manor |
| Independence Mall |
| Iron Hill School No. 112C |
| Isaacs & Sons Cold Storage Building |
| Ivy Dale Farm |
| Ivyside Farm |
Data from United States Park Service and Wikidata
