Connecticut - Criteria: A (event)
| Union Green Historic District |
| Union School |
| Union Society of Phoenixville House |
| Union Station |
| Union Village Historic District |
| Unitarian Meetinghouse |
| United Bank Building |
| United Illuminating Company Building |
| United States Housing Corporation Historic District |
| 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 and Federal Building |
| U.S.S. NAUTILUS (submarine) |
| Valley Falls Cotton Mill Site |
| Viets' Tavern |
| Villa Friuli |
| Village Creek |
| Wadsworth Atheneum |
| Wallingford Center Historic District |
| Wall Street Historic District |
| Walnut Grove |
| Warner Theatre |
| War Office |
| Warren Congregational Church |
| Warrenton Woolen Mill |
| Washington Avenue Bridge |
| Washington Bridge |
| Washington Green Historic District |
| Washington School |
| Waterbury Clock Company |
| Waterbury Municipal Center Complex |
| Waterbury Union Station |
| Watertown Center Historic District |
| Watkinson Juvenile Asylum and Farm School |
| Wauregan Historic District |
| Webb, David Jr. and Sarah, House |
| Webb, Joseph, House |
| Webster Memorial Building |
| Webster, Noah, Memorial Library |
| Webster School |
| Welch, David, House |
| Welch Training School |
| Wells, John, Jr., House |
| West Boulevard Historic District |
| Westbrook Town Center Historic District |
| West End Commercial District |
| West End North Historic District |
| West Goshen Historic District |
| West Granby Historic District |
| West Haven Green Historic District |
| West Hill Historic District |
| Westport Bank and Trust Company |
| West Street School |
| Westville Village Historic District |
| Wethersfield Avenue Car Barn |
| Whale Oil Row |
| Wheeler, Adin, House and Theodore F. Wheeler Wheelwright Shop |
| Wheeler Block |
| White-Overton-Callander House |
| White's Tavern |
| Whitfield Cowles House |
| Whitman House |
| Whitney Avenue Historic District |
| Whitneyville Congregational Church |
| Wiard, John, House |
| Wickham Road Historic District |
| Widows' Home |
| Wilby High School |
| Wilcox, Crittenden Mill |
| Wildman, E. A., & Co. Tobacco Warehouse |
| William Clark Company Thread Mill |
| Williams, Austin F., Carriagehouse and House |
| Williams, Captain Benjamin House |
| Williams House |
| Williams, J. B., Co. Historic District |
| Williams Memorial Institute |
| Williams Memorial Park Historic District |
| Willimantic Armory |
| Willimantic Elks Club |
| Willimantic Footbridge |
| Willimantic Freight House and Office |
| Wilton Center Historic District |
| Winchester Repeating Arms Company Historic District |
| Winchester Soldiers' Monument |
| Windsor Avenue Congregational Church |
| Windsor Farms Historic District |
| Windsor Locks Passenger Station |
| Winsted Green Historic District |
| Winsted Hosiery Mill |
| Winthrop Mill |
| Wolcott Green Historic District |
| Woodbridge Farm |
| Woodbridge Farmstead |
| Woodbury Historic District No. 1 |
| Woodbury Historic District No. 2 |
| Wood, Harcourt, Memorial Library |
| Woodrow Wilson High School |
Data from United States Park Service and Wikidata
