| Agudath Sholem Synagogue | Stamford | Building | 1995 |
| Allen House, The | Westport | Building | 2010 |
| Aspetuck Historic District | Easton | District | 1991 |
| BERKSHIRE NO. 7 | Bridgeport | Structure | 1978 |
| Baldwin, Caleb, Tavern | Newtown | Building | 2002 |
| Ball and Roller Bearing Company | Danbury | Building | 1989 |
| Barlow, Aaron, House | Redding | Building | 1982 |
| Barnum Institute of Science and History NHL | Bridgeport | Building | |
| Barnum Museum | Bridgeport | Building | 1972 |
| Barnum/Palliser Historic District | Bridgeport | District | 1982 |
| Bartlett, Daniel and Esther, House | Redding | Building | 1993 |
| Basset, Daniel, House | Monroe | Building | 2002 |
| Bassickville Historic District | Bridgeport | District | 1987 |
| Beardsley Park | Bridgeport | District | 1999 |
| Benedict House and Shop | Ridgefield | Building | 1998 |
| Beth Israel Synagogue | Norwalk | Building | 1991 |
| Bikur Cholim Synagogue | Bridgeport | Building | 1995 |
| Birdcraft Sanctuary NHL | Fairfield | Site | 1982 |
| Bishop, Peyton Randolph, House | Bridgeport | Building | 1987 |
| Bishop, William D., Cottage Development Historic District | Bridgeport | District | 1982 |
| Black Rock Gardens Historic District | Bridgeport | District | 1990 |
| Black Rock Historic District | Bridgeport | District | 1979 |
| Booth, Nathan B., House | Stratford | Building | 1992 |
| Boothe Homestead | Stratford | District | 1985 |
| Boston Post Road Historic District | Darien | District | 1982 |
| Bradley Edge Tool Company Historic District | Weston | District | 1995 |
| Bradley-Hubbell House | Easton | Building | 2003 |
| Bradley-Wheeler House | Westport | Building | 1984 |
| Branchville Railroad Tenement | Ridgefield | Building | 1982 |
| Breuer, Marcel, House II | New Canaan | Building | 2010 |
| Bridge Street Historic District | Westport | District | 2018 |
| Bridgeport City Hall | Bridgeport | Building | 1977 |
| Bridgeport Downtown North Historic District | Bridgeport | District | 1987 |
| Bridgeport Downtown South Historic District | Bridgeport | District | 1987 |
| Bronson Windmill | Fairfield | Structure | 1971 |
| Brookfield Center Historic District | Brookfield Center | District | 1991 |
| Bush-Holley House NHL | Greenwich | Building | 1988 |
| Byram School | Greenwich | Building | 1990 |
| Cain, Hugh, Fulling Mill and Elias Glover Woolen Mill Archeological Site | Ridgefield | Site | 1985 |
| Camps Nos. 10 and 41 of Rochambeau's Army | Newtown | Site | 2002 |
| Cannondale Historic District | Wilton | District | 1992 |
| Cassidy House | Bridgeport | Building | 2011 |
| Chichester Road Historic District | New Canaan | District | 2026 |
| Chivvis, Arthur and Lyn, House | New Canaan | Building | 2010 |
| Christ Episcopal Church and Tashua Burial Ground | Trumbull | Building | 2001 |
| Church of the Holy Name | Stamford | Building | 1987 |
| Commodore Hull School | Shelton | Building | 1983 |
| Compo-Owenoke Historic District | Westport | District | 1991 |
| Comstock, Abijah, House | New Canaan | Building | 2017 |
| Connecticut Railway and Lighting Company Car Barn | Bridgeport | Building | 1987 |
| Cos Cob Power Station | Greenwich | District | 1990 |
| Cos Cob Railroad Station | Greenwich | Building | 1989 |
| Cosier-Murphy House | New Fairfield | Building | 1991 |
| Cove Island Houses | Stamford | Building | 1979 |
| Curtis, Nathaniel, House | Stratford | Building | 1982 |
| Davenport, Deacon John, House | Stamford | Building | 1982 |
| Davenport, Hanford, House | New Canaan | Building | 1989 |
| Deacon's Point Historic District | Bridgeport | District | 1992 |
| Division Street Historic District | Bridgeport | District | 1982 |
| Downtown Bridgeport Historic District | Bridgeport | District | 2025 |
| Downtown Stamford Historic District | Stamford | District | 1983 |
| Downtown Stamford Historic District (Boundary Increase 2) | Stamford | District | 2003 |
| Downtown Stamford Historic District (Boundary Increase) | Stamford | District | 1985 |
| Dr. Harvey and Rhoda Wasserman House | Weston | Building | 2024 |
| Durisol House | New Canaan | Building | 2010 |
| ELMER S. DAILEY | Bridgeport | Structure | 1978 |
| Eagle's Nest | Bridgeport | Building | 1979 |
| East Bridgeport Historic District | Bridgeport | District | 1979 |
| East Main Street Historic District | Bridgeport | District | 1985 |
| Ein Jacob (Ayn Yacob) Synagogue | Bridgeport | Building | 1995 |
| Ely, Rev. John, House | Bethel | Building | 2001 |
| Fairfield County Courthouse | Bridgeport | Building | 1982 |
| Fairfield County Jail | Bridgeport | Building | 1985 |
| Fairfield Hills Campus Historic District | Newtown | District | 2024 |
| Fairfield Historic District | Fairfield | Building | 1971 |
| Fairfield Railroad Stations | Fairfield | Building | 1989 |
| Ferris, Samuel, House | Greenwich | Building | 1989 |
| First Baptist Church | Bridgeport | Building | 1990 |
| First Presbyterian Church NHL | Stamford | Building | |
| First Presbyterian Church NHL | Stamford | Building | |
| Five Mile River Landing Historic District | Norwalk | District | 2009 |
| Ford, Elinor and Sherman, House | New Canaan | Building | 2010 |
| Fort Stamford Site | Stamford | Site | 1975 |
| Fourth Ward Historic District | Greenwich | District | 2000 |
| Freeman, Mary and Eliza, Houses | Bridgeport | Building | 1999 |
| French Farm | Greenwich | Building | 1975 |
| Gallaher Estate | Norwalk | District | 2011 |
| Gateway Village Historic District | Bridgeport | District | 1990 |
| Georgetown Historic District | Redding | District | 1987 |
| Glenville Historic District | Greenwich | District | 2007 |
| Glenville School | Greenwich | Building | 2003 |
| Glover House | Newtown | Building | 1982 |
| Glover, John, House | Newtown | Building | 2001 |
| Godillot Place | Westport | Building | 1977 |
| Golden Hill Historic District | Bridgeport | District | 1987 |
| Gores, Landis, House | New Canaan | Building | 2002 |
| Graham House | Stamford | Building | 2011 |
| Great Captain Island Lighthouse | Greenwich | Building | 1991 |
| Green Farms School | Westport | Building | 1991 |
| Greenfield Hill Grange #133 | Fairfield | Building | 2008 |
| Greenfield Hill Historic District | Greenfield Hill | District | 1971 |
| Greens Ledge Lighthouse | Rowayton | Structure | 1990 |
| Greenwich Avenue Historic District | Greenwich | District | 1989 |
| Greenwich Municipal Center Historic District | Greenwich | District | 1988 |
| Greenwich Point Historic District | Greenwich | District | 2021 |
| Greenwich Town Hall | Greenwich | Building | 1987 |
| Greenwich YMCA | Greenwich | Building | 1996 |
| Greenwood Avenue Historic District | Bethel | District | 1999 |
| Hait, Benjamin, House | Stamford | Building | 1978 |
| Hall, Isaac Davis and Marion Dalton, House | New Canaan | Building | 2010 |
| Hampton Inn | New Canaan | Building | 2004 |
| Hattertown Historic District | Newtown | District | 1996 |
| Haviland and Elizabeth Streets-Hanford Place Historic District | Norwalk | District | 1988 |
| Hawley, Thomas, House | Monroe | Building | 1980 |
| Hearthstone | Danbury | Building | 1987 |
| Hebrew Congregation of Woodmont | Milford | Building | 1995 |
| Hodgson, Richard and Geraldine, House | New Canaan | Building | 2005 |
| Hotel Beach | Bridgeport | Building | 1978 |
| Housatonic River Railroad Bridge | Milford-Stratford | Structure | 1987 |
| Hoyt-Barnum House | Stamford | Building | 1969 |
| Hoyt-Burwell-Morse House | New Canaan | Building | 2017 |
| Hubbard Heights Historic District | Stamford | District | 2016 |
| Huntington Center Historic District | Shelton | District | 2000 |
| Hurlbutt Street School | Wilton | Building | 1996 |
| Hyatt, Thomas, House | Ridgefield | Building | 1984 |
| Indian Harbor Yacht Club | Greenwich | Building | 2010 |
| Ives, Charles, House | Danbury | Building | 1976 |
| Jennie Leeds Gardener Cottage | Stamford | Building | 2026 |
| Johnson, Philip, Glass House NHL | New Canaan | District | 1997 |
| Judson, Capt. David, House | Stratford | Building | 1973 |
| June, Lewis, House | Ridgefield | Building | 1984 |
| Keeler Tavern | Ridgefield | Building | 1982 |
| Kellogg, Enos, House | Norwalk | Building | 2012 |
| Kettle Creek Historic District | Weston | District | 1995 |
| Kings Highway North Historic District | WEstport | District | 1998 |
| Knap, John, House | Stamford | Building | 1979 |
| Knapp Tavern | Greenwich | Building | 1977 |
| Lakeview Village Historic District | Bridgeport | District | 1990 |
| Lambert, David, House | Wilton | Building | 1992 |
| Lattin, Nathan B., Farm | Newtown | Building | 1990 |
| Le Roy Shirt Company Factory | Norwalk | Building | 2012 |
| Lee, John Black, House I | New Canaan | Building | 2010 |
| Lewis, Isaac, House | Stratford | Building | 1991 |
| Linden Apartments | Stamford | Building | 1983 |
| Little Bethel African Methodist Episcopal Church | Greenwich | Building | 2010 |
| Lockwood-Mathews Mansion NHL | Norwalk | Building | 1970 |
| Locust Avenue School | Danbury | Building | 1985 |
| Long Ridge Village Historic District | Stamford | District | 1987 |
| Long Ridge Village Historic District (Boundary Increase) | Stamford | District | 2011 |
| Loth, Joseph, Company Building | Norwalk | Building | 1984 |
| Lounsbury, Phineas Chapman, House | Ridgefield | Building | 1975 |
| Lyon, Thomas, House | Greenwich | Building | 1977 |
| Main Street Bridge | Stamford | Structure | 1987 |
| Main Street Historic District | Danbury | District | 1983 |
| Mallett, David, Jr., House | Trumbull | Building | 1986 |
| Maplewood School | Bridgeport | Building | 1990 |
| March Route of Rochambeau's Army: Reservoir Road | Newtown | District | 2003 |
| March Route of Rochambeau's Army: Ridgebury Road | Ridgefield | District | 2003 |
| Marina Park Historic District | Bridgeport | District | 1982 |
| Marion Castle, Terre Bonne | Stamford | Building | 1982 |
| Marvin Tavern | Wilton | Building | 1984 |
| Mather, Stephen Tyng, House NHL | Darien | Building | 1966 |
| Meadowlands | Darien | Building | 1987 |
| Meeker's Hardware | Danbury | Building | 1983 |
| Merritt Parkway | Greenwich | District | 1991 |
| Methodist Episcopal Church | Greenwich | Building | 1988 |
| Mianus River Railroad Bridge | Greenwich | Structure | 1987 |
| Mill Cove Historic District | Westport | District | 1991 |
| Mills, Beaven W., House | New Canaan | Building | 2010 |
| Mills, Willis N, House | New Canaan | Building | 2010 |
| Monroe Center Historic District | Monroe | District | 1977 |
| Morris and Rose Greenwald House | Weston | Building | 2024 |
| Murphy, Charles and Peggy House | New Canaan | Building | 2010 |
| Nathaniel Wheeler Memorial Fountain | Bridgeport | Object | 1985 |
| Nathaniel Witherell Historic District | Greenwich | District | 2010 |
| National Hall Historic District | Westport | District | 1984 |
| New Haven Railroad Danbury Turntable | Danbury | Structure | 2005 |
| New Mill and Depot Building, Hawthorne Woolen Mill | Greenwich | Building | 1990 |
| New York Belting and Packing Co. | Newtown | District | 1982 |
| Newtown Borough Historic District | Newtown | District | 1996 |
| Nichols Farms Historic District | Trumbull | District | 1987 |
| Nichols Satinet Mill Site | Newtown | Site | 1996 |
| Norfield Historic District | Weston | District | 1991 |
| Norwalk City Hall | Norwalk | Building | 1995 |
| Norwalk Green Historic District | Norwalk | District | 1987 |
| Norwalk Island Lighthouse | Norwalk | Building | 1989 |
| Norwalk River Railroad Bridge | South Norwalk | Structure | 1987 |
| Noyes House | New Canaan | Building | 2008 |
| Octagon House | Danbury | Building | 1973 |
| Octagon House | Stamford | Building | 1979 |
| Ogden, David, House | Fairfield | Building | 1979 |
| Old Mine Park Archeological Site | Trumbull | Site | 1990 |
| Old Town Hall | Stamford | Building | 1972 |
| Osborne, John, House | Fairfield | Building | 1987 |
| Oysterman's Row | Norwalk | District | 2010 |
| PRICILLA DAILEY | Bridgeport | Structure | 1978 |
| Palace and Majestic Theaters | Bridgeport | Building | 1979 |
| Park Apartments | Bridgeport | Building | 1990 |
| Peck Ledge Lighthouse | Norwalk | Structure | 1990 |
| Penfield Reef Lighthouse | Bridgeport | Structure | 1990 |
| Pequonnock River Railroad Bridge | Bridgeport | Structure | 1987 |
| Perkins, Maxwell E., House | New Canaan | Building | 2004 |
| Perry Avenue Bridge | Norwalk | Structure | 2006 |
| Perry, David, House | Bridgeport | Building | 1984 |
| Pike, Gustavus and Sarah T., House | Stamford | Building | 1990 |
| Pine Creek Park Bridge | Fairfield | Structure | 1992 |
| Plumb Memorial Library | Shelton | Building | 1978 |
| Pond-Weed House | Darien | Building | 1978 |
| Putnam Hill Historic District | Greenwich | District | 1979 |
| Putnam Memorial State Park | Redding | Site | 1970 |
| Railroad Avenue Industrial District | Bridgeport | District | 1985 |
| Redding Center Historic District | Redding | District | 1992 |
| Remington City Historic District | Bridgeport | District | 1990 |
| Remington Village Historic District | Bridgeport | District | 1990 |
| Remington, Frederic, House NHL | Ridgefield | Building | 1966 |
| Restmore | Fairfield | Building | 2009 |
| Revonah Manor Historic District | Stamford | District | 1986 |
| Rider, John, House | Danbury | Building | 1977 |
| Ridgebury Congregational Church | Ridgebury | Building | 1984 |
| Ridgefield Center Historic District | Ridgefield | District | 1984 |
| River Road-Mead Avenue Historic District | Greenwich | District | 2014 |
| Riverside Avenue Bridge | Greenwich | Structure | 1977 |
| Robinson, P., Fur Cutting Company | Danbury | Building | 1982 |
| Rock Ledge | Norwalk | Building | 1977 |
| Rockrimmon Rockshelter | Stamford | Site | 1994 |
| Rogers, John, Studio NHL | New Canaan | Building | 1966 |
| Rosemary Hall | Greenwich | Building | 1998 |
| Round Hill Historic District | Greenwich | District | 1996 |
| Rowayton Depot Historic District | Norwalk | District | 2019 |
| Sanford-Curtis-Thurber House | Newtown | Building | 2007 |
| Saugatuck River Bridge | Westport | Structure | 1987 |
| Saugatuck River Railroad Bridge | Westport | Structure | 1987 |
| Seaside Institute | Bridgeport | Building | 1982 |
| Seaside Park | Bridgeport | Site | 1982 |
| Seaside Village Historic District | Bridgeport | District | 1990 |
| Seelye, Seth, House | Bethel | Building | 1977 |
| Selleck, Sylvanus, Gristmill | Greenwich | Building | 1990 |
| Shambaugh House | Westport | Building | 1999 |
| Sherman Historic District | Sherman | District | 1991 |
| Silvermine Center Historic District | Norwalk | District | 2009 |
| Sloan-Raymond-Fitch House | Wilton | Building | 1982 |
| Sound Beach Railroad Station | Greenwich | Building | 1989 |
| South End Historic District | Stamford | District | 1986 |
| South Main and Washington Streets Historic District | Norwalk | District | 1977 |
| South Main and Washington Streets Historic District (Boundary Increase II) | Norwalk | District | 1999 |
| South Main and Washington Streets Historic District (Boundary Increase) | Norwalk | District | 1985 |
| Southport Historic District | Fairfield | District | 1971 |
| Southport Railroad Stations | Fairfield | Building | 1989 |
| St. Andrew's Protestant Episcopal Church | Stamford | Building | 1983 |
| St. Benedict's Church | Stamford | Building | 1987 |
| St. John's Episcopal Church | Bridgeport | Building | 1984 |
| St. John's Protestant Episcopal Church | Stamford | Building | 1987 |
| St. Luke's Chapel | Stamford | Building | 1987 |
| St. Mark’s Episcopal Church | New Canaan | Building | 2021 |
| St. Mary's Church | Stamford | Building | 1987 |
| Stamford Harbor Lighthouse | Stamford | Building | 1991 |
| Starr, C. J., Barn and Carriage House | Stamford | Building | 1979 |
| Sterling Block-Bishop Arcade | Bridgeport | Building | 1978 |
| Sterling Hill Historic District | Bridgeport | District | 1992 |
| Sterling Homestead | Stratford | Building | 1976 |
| Stevenson Dam Hydroelectric Plant | Stevenson | Structure | 2000 |
| Stratfield Historic District | Bridgeport | District | 1980 |
| Stratford Center Historic District | Stratford | District | 1983 |
| Stratford Point Lighthouse | Stratford | Structure | 1990 |
| Strickland Road Historic District | Greenwich | District | 1990 |
| Sturges, Jonathan, House NHL | Fairfield | Building | 1984 |
| Sturges-Wright House | Westport | Building | 2015 |
| Suburban Club | Stamford | Building | 1989 |
| Swallen, James, House | New Canaan | Building | 2010 |
| System House | New Canaan | Building | 2010 |
| Tarbell, Ida, House NHL | Easton | Building | 1993 |
| Tarrywile | Danbury | Building | 1988 |
| Tatum, Corinne and George Liston Jr., House | New Canaan | Building | 2010 |
| The Lodges Historic District | Norwalk | District | 2020 |
| Titicus Hill Historic District | Ridgefield | District | 2012 |
| Tongue Point Lighthouse | Bridgeport | Structure | 1990 |
| Town Hall | Westport | Building | 1982 |
| Turn-of-River Bridge | Stamford | Structure | 1987 |
| US Post Office-Bridgeport Main | Bridgeport | Building | 1986 |
| US Post Office-Greenwich Main | Greenwich | Building | 1986 |
| US Post Office-South Norwalk Main | Norwalk | Building | 1986 |
| US Post Office-Stamford Main | Stamford | Building | 1985 |
| Umpawaug District School | Redding | Building | 1988 |
| Union Station | Danbury | Building | 1986 |
| Unitarian-Universalist Church | Stamford | Building | 1987 |
| United Congregational Church | Bridgeport | Building | 1984 |
| United Illuminating Company Building | Bridgeport | Building | 1985 |
| United States Post Office, Westport, Connecticut | Westport | Building | 2012 |
| Verneur Pratt Historic District | Norwalk | District | 2011 |
| Village Creek | Norwalk | District | 2010 |
| Wall Street Historic District | Norwalk | District | 2009 |
| Waltersville School | Bridgeport | Building | 2025 |
| Waveny | New Canaan | District | 2019 |
| Webb, David Jr. and Sarah, House | New Canaan | Building | 2011 |
| Weir Farm National Historic Site | Wilton | District | 1990 |
| Weir, J. Alden, Farm Historic District | Ridgefield | District | 1984 |
| West End Congregation-Achavath Achim Synagogue | Bridgeport | Building | 1995 |
| West Mountain Historic District | Ridgefield | District | 1984 |
| Westport Bank and Trust Company | Westport | Building | 2006 |
| Westport Center Historic District | Westport | District | 2016 |
| Wheeler, Ephraim, House | Stratford | Building | 1992 |
| Whistleville Historic District | Norwalk | District | 2021 |
| Wilcox, Josiah, House | Greenwich | Building | 1988 |
| Williams House | New Fairfield | Building | 2014 |
| Wilmot Apartments Historic District | Bridgeport | District | 1990 |
| Wilton Center Historic District | Wilton | District | 1992 |
| Zion Lutheran Church | Stamford | Building | 1987 |