Connecticut - Criteria: C (architecture/engineering)
| Crawford, George W., Manor |
| Cream Hill Agricultural School |
| Cream Hill Shelter |
| Curtis Memorial Library |
| Curtis, Nathaniel, House |
| Curtiss, Reuben, House |
| Curtisville Historic District |
| Dana, James Dwight, House |
| Daniels, Charles, House |
| Danielson Main Street Historic District |
| Daniel's Village Archeological Site |
| Darling Family Farmstead and Tavern |
| Darling, Robert and Julia, House |
| Davenport, Deacon John, House |
| Davenport, Hanford, House |
| Day, Amasa, House |
| Day, Calvin, House |
| Day House |
| Day-Taylor House |
| Dayville Historic District |
| Deacon's Point Historic District |
| Deane, Silas, House |
| Deep River Freight Station |
| Deep River Town Hall |
| Department Store Historic District |
| Depot Street Bridge |
| Deshon-Allyn House |
| Dickerman II, Jonathan, House |
| Dillon Building |
| Division Street Historic District |
| Dixwell Avenue Congregational United Church of Christ |
| Doane's Sawmill/Deep River Manufacturing Company |
| DORIS (Sailing yacht) |
| Downtown Main Street Historic District |
| Downtown New Britain |
| Downtown New London Historic District |
| Downtown North Historic District |
| Downtown Norwich Historic District |
| Downtown Seymour Historic District |
| Downtown Torrington Historic District |
| Downtown Waterbury Historic District |
| Drake Hill Road Bridge |
| Dudley, Jedidiah, House |
| Dudleytown Historic District |
| Durisol House |
| Dwight Street Historic District |
| East Bridgeport Historic District |
| East District School |
| East Granby Historic District |
| East Haddam Historic District |
| East Haven Green Historic District |
| East Main Street Historic District |
| East Plymouth Historic District |
| East Rock Park |
| East Weatogue Historic District |
| East Windsor Academy |
| East Windsor Hill Historic District |
| Eclectic House, The |
| Edgerton |
| Edgewood Park Historic District |
| Eells-Stow House |
| Ein Jacob (Ayn Yacob) Synagogue |
| Elam Ives House |
| Eldredge Mills Archeological District |
| Eliot, Samuel, House |
| Elizabeth Park |
| Ellington Center Historic District |
| Elliottville Lower Mill |
| Ellsworth, Horace H., House |
| Ellsworth, Oliver, Homestead |
| Elmore Houses |
| Elm Street Historic District |
| Elm Street Historic District |
| Elton Hotel |
| Ely, Rev. John, House |
| EMMA C. BERRY (Fishing Sloop) |
| Emmanuel Church |
| Endee Manor Historic District |
| Enfield Canal |
| Enfield Historic District |
| Enfield Shakers Historic District |
| Enfield Town Meetinghouse |
| Engine Company 15 Fire Station |
| Engine Company 16 Fire Station |
| Engine Company 1 Fire Station |
| Engine Company 2 Fire Station |
| Engine Company 6 Fire Station |
| Engine Company 9 Fire Station |
| Eno Memorial Hall |
| Eolia-Harkness Estate |
| Erwin Home for Worthy and Indigent Women |
| Esperanza |
| Essex Freight Station |
| Evans, Ebenezer, House |
| Fairfield Avenue Historic District |
| Fairfield County Courthouse |
| Fairfield County Jail |
| Fairfield Historic District |
| Falkner's Island Lighthouse |
| Falls Village District |
Data from United States Park Service and Wikidata
