| Abyssinian Meeting House | Portland | Building | 2006 |
| Academy Building | Gorham | Building | 1973 |
| Andrews, Lt. Robert, House | Bridgton | Building | 2005 |
| Androscoggin Swinging Bridge | Brunswick | Structure | 2004 |
| Art Gallery | Gorham | Building | 1972 |
| Auburn-Harpswell Association Historic District | South Harpswell | District | 1985 |
| BAGHEERA (schooner) | Portland | Structure | 2009 |
| Back Cove | Portland | District | 1989 |
| Bailey Island Cobwork Bridge | Harpswell | Structure | 1975 |
| Bailey Island Library Hall | Harpswell | Building | 2008 |
| Battery Steele | Portland | Structure | 2005 |
| Baxter House | Gorham | Building | 1979 |
| Baxter Summer Home | Falmouth | Building | 1985 |
| Beckett's Castle | Cape Elizabeth | Building | 1974 |
| Blanchard, Capt. S. C., House | Yarmouth | Building | 1979 |
| Boody, Henry, House | Brunswick | Building | 1975 |
| Brown, C. A., Cottage | Cape Elizabeth | Building | 1974 |
| Brown, Harrison B., House | Portland | Building | 1980 |
| Brown, J. B., Memorial Block | Portland | Building | 1978 |
| Brunswick Commercial Historic District | Brunswick | District | 2016 |
| Burnell Tavern | West Baldwin | Building | 1983 |
| Butler, A. B., House | Portland | Building | 1974 |
| Camp Hammond | Yarmouth | Building | 1979 |
| Caswell Public Library (Former) | Harrison | Building | 2005 |
| Cathedral of the Immaculate Conception | Portland | Building | 1985 |
| Central Parish Church | Yarmouth | Building | 1988 |
| Chapman, Leonard Bond, House | Portland | Building | 1980 |
| Chestnut Street Methodist Church | Portland | Building | 1977 |
| Children's Hospital | Portland | Building | 2012 |
| Clapp, Charles Q., Block | Portland | Building | 1978 |
| Clapp, Charles Q., House | Portland | Building | 1972 |
| Cleaveland, Parker, House NHL | Brunswick | Building | 2000 |
| Cleaves, Benjamin, House | Bridgton | Building | 1988 |
| Clifford, Nathan, School | Portland | Building | 2013 |
| Cousins Island Chapel | Cousins Island | Building | 1997 |
| Crescent Lodge | Cape Elizabeth | Building | 2018 |
| Crystal Spring Farm | Brunswick | District | 2004 |
| Cumberland Mills Historic District | Westbrook | District | 1974 |
| Cumberland and Oxford Canal | Standish | Structure | 1974 |
| Davis, Dalton Holmes, Memorial Library | Bridgton | Building | 1989 |
| Deering Estate Barn | Portland | Building | 1969 |
| Deering Oaks | Portland | District | 1989 |
| Deering Street Historic District | Portland | District | 1983 |
| Deertrees Theatre | Harrison | Building | 1989 |
| Dow Bridge | Standish | Structure | 2022 |
| Dow, Gen. Neal, House NHL | Portland | Building | 1973 |
| Dry Mills School | Gray | Building | 1996 |
| Dunlap, John, House | Brunswick | Building | 1979 |
| Dunning, Deacon Andrew, House | North Harpswell | District | 1999 |
| Dunstan Methodist Episcopal Church | Scarborough | Building | 1989 |
| Dyer, Isaac E., Estate | Gorham | District | 1998 |
| Dyer, Nathaniel, House | Portland | Building | 1987 |
| Dyer-Hutchinson Farm | Cape Elizabeth | District | 1997 |
| Dyke Mountain Annex | Sebago | Building | 2005 |
| Eagle Island NHL | Harpswell | Building | 1971 |
| East Harpswell Free Will Baptist Church | East Harpswell | Building | 1988 |
| East Raymond Union Chapel | East Raymond | Building | 2004 |
| Eastern Cemetery | Portland | Site | 1973 |
| Eastern Promenade | Portland | District | 1989 |
| Eighth Maine Regiment Memorial | Peaks Island | Building | 2006 |
| Engine Company Number Nine Firehouse | Portland | Building | 2010 |
| Everett Chambers | Portland | Building | 2006 |
| Evergreen Cemetery | Portland | District | 1992 |
| Falmouth High School | Falmouth | Building | 2016 |
| Falmouth House | North Falmouth | Building | 1976 |
| Farnsworth House | North Bridgton | Building | 1980 |
| Federal Street Historic District | Brunswick | District | 1976 |
| Fifth Maine Regiment Community Center | Portland | Building | 1978 |
| First Parish Church | Brunswick | Building | 1969 |
| First Parish Church | Portland | Building | 1973 |
| First Parish Congregational Church | Yarmouth | Building | 1995 |
| First Parish Meetinghouse | Standish | Building | 1975 |
| Fitch's General Store and House | East Sebago | Building | 1995 |
| Fort Gorges | Portland | Structure | 1973 |
| Fort McKinley Historic District | Portland | District | 1985 |
| Fort McKinley Torpedo Storehouse | Portland | Building | 2024 |
| Franklin Towers | Portland | Building | 2024 |
| Freeman Farm Historic District | Gray | District | 2003 |
| Freeport Main Street Historic District | Freeport | District | 1977 |
| Friends Meetinghouse | Casco | Building | 1975 |
| Goold House | Windham | Building | 1990 |
| Gorham Campus Historic District | Gorham | Building | 1978 |
| Gorham Historic District | Gorham | District | 1992 |
| Gothic House, The | Portland | Building | 1974 |
| Grand Trunk Railroad Station | Yarmouth | Building | 1979 |
| Great Chebeague Golf Club | Chebeague Island | District | 2015 |
| Great Falls Historic District | North Gorham | District | 1995 |
| Green Memorial A.M.E. Zion Church | Portland | Building | 1973 |
| Greene Cottage | Harpswell | Building | 2019 |
| Greenough, Byron, Block | Portland | Building | 1977 |
| Greenwood Garden Playhouse | Portland | Building | 2021 |
| Griffin House | Portland | Building | 1984 |
| Halfway Rock Light Station | South Harpswell | Structure | 1988 |
| Hall's Tavern | Falmouth | Building | 1978 |
| Hamblen Block | Portland | Building | 1983 |
| Hamblen Development Historic District | Portland | District | 1992 |
| Hanson, Asa, Block | Portland | Building | 2001 |
| Harpswell Meetinghouse NHL | Brunswick | Building | 1968 |
| Harraseeket Historic District | Freeport | District | 1974 |
| Harris, Nathan, House | Westbrook | Building | 1993 |
| Hawthorne, Nathaniel, Boyhood Home | South Casco | Building | 1969 |
| Homer, Winslow, Studio NHL | Scarborough | Building | 1966 |
| How Houses | Portland | District | 1980 |
| How, Daniel, House | Portland | Building | 1973 |
| Hunniwell, Richard, House | Scarborough | Building | 1976 |
| Ingraham, Joseph Holt, House | Portland | Building | 1973 |
| Intervale Farm | New Gloucester | Building | 2004 |
| Kellogg, Elijah, Church | Harpswell | Building | 1979 |
| Kellogg, Elijah, House | Harpswell | Building | 1975 |
| Lakeside Grange #63 | Harrison | Building | 2005 |
| Lancaster Block | Portland | Building | 1982 |
| Leighton, Adam P., House | Portland | Building | 1982 |
| Lightship No. 112, NANTUCKET NHL | South Portland | Structure | 1989 |
| Lincoln Park | Portland | District | 1989 |
| Lincoln Street Historic District | Brunswick | District | 1976 |
| Little Mark Island Monument | Harpswell | Structure | 2016 |
| Longfellow, Henry Wadsworth, Monument | Portland | Object | 1990 |
| Longfellow, Stephen, House | Gorham | Building | 1984 |
| Maine Archeological Site No. 9-16 | Portland | Site | 1979 |
| Maine Central Railroad General Office Building | Portland | Building | 1988 |
| Maine Eye and Ear Infirmary | Portland | Building | 1986 |
| Maine Historical Society | Portland | Building | 1980 |
| Maine Publicity Bureau Building | Portland | Building | 1990 |
| Mallett Hall | Pownal Center | Building | 1991 |
| Mallett, E. B., Office Building | Freeport | Building | 1982 |
| Manning, Richard, House | South Casco | Building | 1993 |
| Manor House | Naples | Building | 1978 |
| Maplewood Farm | South Windham | District | 1991 |
| Marine Hospital | Portland | Building | 1974 |
| Mariner's Church | Portland | Building | 1973 |
| Marrett, Daniel, House | Standish | Building | 1974 |
| Masonic Temple | Portland | Building | 1982 |
| Massachusetts Hall, Bowdoin College | Brunswick | Building | 1971 |
| McLellan House | Gorham | Building | 1972 |
| McLellan-Sweat Mansion NHL | Portland | Building | 1970 |
| Mechanics' Hall | Portland | Building | 1973 |
| Mechanics' Hall (Additional Documentation) | Portland | Building | 1973 |
| Merriconeag Grange No. 425 | Harpswell | Building | 2019 |
| Merriconegan Farm | Harpswell | Building | 1979 |
| Merrill, Capt. Reuben, House | Yarmouth | Building | 1974 |
| Merrill, Capt. Reuel and Lucy, House | Cumberland Center Station | Building | 1999 |
| Minott, William, House | Portland | Building | 1979 |
| Mitchell House | Yarmouth | Building | 1978 |
| Morse-Libby Mansion NHL | Portland | Building | 1970 |
| New Gloucester Historic District | New Gloucester | District | 1974 |
| North School | Portland | Building | 1982 |
| North Yarmouth Academy | Yarmouth | Building | 1975 |
| North Yarmouth and Freeport Baptist Meetinghouse | Yarmouth | Building | 1978 |
| Norton House Historic District | Falmouth | Building | 2004 |
| Orr's Island Meeting House | Harpswell | Building | 2022 |
| Paine Neighborhood Historic District | Standish | District | 1985 |
| Park Street Row | Portland | Building | 1972 |
| Payson House at Thornhurst | Falmouth | Building | 2005 |
| Peabody-Fitch House | South Bridgton | District | 1989 |
| Pennell Institute | Gray | Building | 1982 |
| Pennellville Historic District | Brunswick | District | 1985 |
| Perley, Sam, Farm | Naples | Building | 1979 |
| Perry, William F., House | Bridgton | Building | 1975 |
| Pettengill House and Farm | Freeport | Building | 1970 |
| Porteous, Mitchell and Braun Company Building | Portland | Building | 1996 |
| Portland Breakwater Light | South Portland | Building | 1973 |
| Portland City Hall | Portland | Building | 1973 |
| Portland City Hospital | Portland | Building | 1985 |
| Portland Club | Portland | Building | 1973 |
| Portland Headlight | Cape Elizabeth | Building | 1973 |
| Portland High School | Portland | Building | 1984 |
| Portland Observatory NHL | Portland | Building | 1973 |
| Portland Packing Company Factory | Portland | Building | 1996 |
| Portland Railroad Company Substation | West Scarborough | Building | 1991 |
| Portland Soldiers and Sailors Monument | Portland | Object | 1998 |
| Portland Waterfront | Portland | District | 1974 |
| Portland Waterfront (Boundary Increase) | Portland | District | 2012 |
| Portland Waterfront Historic District (Boundary Increase III) | Portland | District | 2020 |
| Portland Waterfront Historic District (Boundary Increase) | Portland | District | 1984 |
| Pote, Capt. Greenfield, House | Freeport | Building | 1970 |
| Pownal Cattle Pound | Pownal | Structure | 2004 |
| Prince, Cushing and Hannah, House | Yarmouth | Building | 1999 |
| Proprietors Meeting House and Parish House | S. Buxton | Building | 2001 |
| Purington, Elisha, House | Falmouth | Building | 1985 |
| Rackleff Building | Portland | Building | 1973 |
| Ram Island Ledge Light Station | Cape Elizabeth | Structure | 1988 |
| Randall, Jacob, House | Pownal | Building | 1979 |
| Reed, Amos O., House | Brunswick | Building | 2025 |
| Reed, Thomas Brackett, House NHL | Portland | Building | 1973 |
| Richardson House | Brunswick | Building | 1974 |
| Richmond's Island Archeological Site | Cape Elizabeth | Site | 1978 |
| Russwurm, John B., House | Portland | Building | 1983 |
| Ryefield Bridge | Stuarts Corner | Structure | 1999 |
| Sagamore Village Historic District | Portland | District | 2020 |
| Scarborough High School | Scarborough | Building | 2007 |
| Schlotterbeck and Foss Building | Portland | Building | 2016 |
| Scribner Homestead | Bolsters Mills | Building | 2001 |
| Seavey-Robinson House | South Portland | Building | 1986 |
| Shaker Village NHL | Sabbathday Lake and vicinity | District | 1974 |
| Skelton, Thomas, House | Falmouth | Building | 1973 |
| Smith, F.O.J., Tomb | Portland | Site | 1974 |
| Smith, Parson, House | South Windham | Building | 1973 |
| Songo Lock | Naples | Structure | 1970 |
| South Bridgton Congregational Church | South Bridgton | Building | 1987 |
| South Street Historic District | Gorham | District | 1988 |
| Southgate Farm | Scarborough | Building | 2018 |
| Sparrow House | Portland | Building | 1982 |
| Spring Point Ledge Light Station | South Portland | Structure | 1988 |
| Spring Street Historic District (Additional Documentation) | Portland | District | 1970 |
| Spurwink Congregational Church | Cape Elizabeth | Building | 1970 |
| St. Hyacinth School and Convent | Westbrook | Building | 2013 |
| St. Joseph's Academy and Convent-Catherine McAuley School (Additional Documentation) | Portland | Building | 2017 |
| St. Joseph's Academy and Convent-Catherine McAuley School (Boundary Increase) | Portland | Building | 2022 |
| St. Lawrence Church | Portland | Building | 1979 |
| St. Paul's Church and Rectory | Portland | Building | 1978 |
| St. Paul's Episcopal Church | Brunswick | Building | 1978 |
| Standish Corner Historic District | Standish | District | 1993 |
| State Reform School Historic District | South Portland | District | 1985 |
| Steep Falls Library | Steep Falls | Building | 2004 |
| Stevens, John Calvin, House | Portland | Building | 1973 |
| Stimson Memorial Hall | Gray | Building | 1992 |
| Stone House | Bridgton | Building | 1984 |
| Stover, Capt. Johnson H. Jr., House | Harpswell | Building | 2018 |
| Stowe, Harriet Beecher, House NHL | Brunswick | Building | 1966 |
| Stroudwater Historic District | Portland | District | 1973 |
| Tarr-Eaton House | Harpswell Center | Building | 2001 |
| Tate House NHL | Stroudwater | Building | 1970 |
| Thomas B. Reed School | Portland | Building | 2020 |
| Thompson Block | Portland | Building | 1973 |
| Tracy-Causer Block | Portland | Building | 1994 |
| Trefethen-Evergreen Improvement Association | Portland | Building | 2024 |
| Two Lights | Cape Elizabeth | Structure | 1974 |
| U.S. Courthouse | Portland | Building | 1974 |
| U.S. Customhouse | Portland | Building | 1973 |
| US Post Office-Portland Main | Portland | Building | 1986 |
| Union Church | North Harpswell | Building | 1988 |
| Union Church | Naples | Building | 1994 |
| Union Hotel | Cundy's Harbor | Building | 1985 |
| Universalist Meeting House | New Gloucester | Building | 1988 |
| Vallee Family House | Westbrook | Building | 1988 |
| Valley Lodge | Steep Falls | Building | 1977 |
| Wadsworth-Longfellow House NHL | Portland | Building | 1966 |
| Wales and Hamblen Store | Bridgton | Building | 1990 |
| Walker Memorial Hall | Bridgton | Building | 1983 |
| Walker Memorial Library | Westbrook | Building | 1980 |
| Walking Man Sign | Westbrook | Object | 2019 |
| Warren Block | Westbrook | Building | 1974 |
| Watkins House and Cabins | South Casco | District | 1992 |
| Webb, John and Maria, House | Bridgton | Building | 2013 |
| Westbrook College Historic District | Portland | Building | 1977 |
| Westbrook High School | Westbrook | Building | 1979 |
| Western Cemetery | Portland | Site | 2025 |
| Western Promenade | Portland | District | 1989 |
| Western Promenade Historic District | Portland | District | 1984 |
| Whittier Field Athletic Complex | Brunswick | District | 2017 |
| Williston-West Church and Parish House | Portland | Building | 1980 |
| Winn Road School | Cumberland Center | Building | 1984 |
| Woodman Building | Portland | Building | 1972 |