Delaware - Area of significance: Architecture
| Compton Park Apartments |
| Cool Spring Park Historic District |
| Cool Spring Presbyterian Church |
| Coombe Historic District |
| Cooper House |
| Corbit-Sharp House |
| Cornucopia |
| Correll's Farm and Lawn Supply |
| Coursey, Thomas B., House |
| Cow Marsh Old School Baptist Church |
| Cox, J. W., Dry Goods Store |
| Crosby and Hill Building |
| Cummins, David J., House |
| Cummins, Timothy, House |
| Curtis Mansion |
| Curtis Paper Mill Workers' Houses |
| Dauneport House |
| Davis, Thomas, House |
| Dawson, Dr., House |
| Dean, Joseph, & Son Woolen Mill |
| Deer Park Farm |
| Delaware Academy of Medicine |
| Delaware Avenue Historic District |
| Delaware City Historic District |
| Delaware Trust Building |
| Delmarva Power and Light Building |
| Denny, T. H., House |
| Dickerson Potato House |
| Dickinson, John, House |
| Dilworth 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 |
| Dragon Run Farm |
| Draper-Adkins House |
| Draper House |
| Duck Creek Village |
| Dupont, P. S., High School |
| Durham-Shores House |
| East Brandywine Historic District |
| Eastburn, Davis, Farm |
| Eastburn, J., Barn |
| Egglinton Hall |
| Eighth Street Park Historic District |
| Eliason, A., House |
| Ellendale State Forest Picnic Facility |
| Elm Grange |
| England House and Mill |
| Eratt House |
| Evans, George, House |
| Evans, John, House |
| Evans-West House |
| Exchange Building |
| Fairview |
| Fairview |
| Fairview |
| Fairview |
| Faucett, Peter S., House |
| Fell Historic District |
| Felton Historic District |
| Felton Railroad Station |
| Fenwick Island Lighthouse Station |
| Ferguson, Robert, House |
| Ferris, Zachariah, House |
| Fields Heirs |
| First National Bank of Seaford |
| Fisher Homestead |
| Fisher's Paradise |
| Fleming House |
| Foord & Massey Furniture Company Building |
| Fort Delaware on Pea Patch Island |
| Fort Dupont Historic District |
| Frederica Historic District |
| Friends Meetinghouse |
| Galloway-Walker House |
| Garrett Snuff Mill |
| Garrett Snuff Mills Historic District |
| George Farmhouse |
| Georgetown Coal Gasification Plant |
| Gibraltar |
| Glebe House |
| Glynrich |
| Golden Mine |
| Gordon, J. M., House |
| Govatos'/McVey Building |
| Governor's House |
| Grace United Methodist Church |
| Graham, Robert, House |
| Granite Mansion |
| Grantham-Edwards-McComb House |
| Graves Mill Historic District |
| Gray, Charles, Printing Shop |
| Great Geneva |
| Greenlawn |
Data from United States Park Service and Wikidata
