Connecticut - Area of significance: Architecture
| Trinity Methodist Episcopal Church |
| Trowbridge Square Historic District |
| Trumbull, John, Birthplace |
| Tully, William, House |
| Tunxis Forest Headquarters House |
| Tunxis Forest Ski Cabin |
| Tunxis Hose Firehouse |
| Turner, Dr. Philip, House |
| Tuttle, Bronson B., House |
| Twain, Mark, House |
| Tyler, John, House |
| Tyler, Solomon, House |
| Umpawaug District School |
| Uncasville Mill Historic District |
| Uncasville School |
| Union Baptist Church |
| Union Church/St. Paul's Church |
| Union Depot |
| Union Green Historic District |
| Union School |
| Union Station |
| Union Village Historic District |
| Unitarian Meetinghouse |
| Unitarian-Universalist Church |
| United Bank Building |
| United Congregational Church |
| United Illuminating Company Building |
| United States Housing Corporation Historic District |
| United States Post Office and Court House |
| United States Post Office, Westport, Connecticut |
| University of Connecticut Historic District-Connecticut Agricultural School |
| Upper Albany Historic District |
| Upper Main Street Historic District |
| Upper State Street Historic District |
| U.S. Post Office |
| U. S. Post Office and Federal Building |
| US Post Office-Ansonia Main |
| US Post Office-Bridgeport Main |
| US Post Office-Greenwich Main |
| US Post Office-Manchester Main |
| US Post Office-Meriden Main |
| US Post Office-Milford Main |
| US Post Office-Naugatuck Main |
| US Post Office-New London Main |
| US Post Office-Norwich Main |
| US Post Office-South Norwalk Main |
| US Post Office-Stamford Main |
| Verneur Pratt Historic District |
| Viets' Tavern |
| Villa Bella Vista |
| Villa Friuli |
| Village Creek |
| Vine Street Apartment Buildings |
| Wadsworth Estate Historic District |
| Waldo, Edward, House |
| Wallingford Center Historic District |
| Wallingford Railroad Station |
| Wall Street Historic District |
| Walnut Grove |
| Walnut Hill District |
| Walnut Hill Park |
| Ward-Heitman House |
| Ward, William and Mary, House |
| Ward, William, Jr., House |
| Warner House |
| Warner, Jonathan, House |
| Warner Theatre |
| Warren Congregational Church |
| Warrenton Woolen Mill |
| Washington Green Historic District |
| Washington School |
| Washington Street Historic District |
| Washington Street School |
| Waterbury Clock Company |
| Waterbury Municipal Center Complex |
| Waterbury Union Station |
| Water Street Historic District |
| Watertown Center Historic District |
| Watkinson Juvenile Asylum and Farm School |
| Wauregan Historic District |
| Waveny |
| Webb, David Jr. and Sarah, House |
| Webb, Joseph, House |
| Webster, Horace, Farmhouse |
| Webster Memorial Building |
| Webster, Noah, Memorial Library |
| Webster School |
| Weir, J. Alden, Farm Historic District |
| Welch, David, House |
| Welch Training School |
| Welles, Gideon, House |
| Welles-Shipman-Ward House |
| Wells, John, Jr., House |
| West Boulevard Historic District |
| Westbrook Town Center Historic District |
| West End Commercial District |
| West End Congregation-Achavath Achim Synagogue |
| West End Historic District |
| West End Library |
| West End North Historic District |
Data from United States Park Service and Wikidata
