| Alliance Clay Product Company | Alliance | District | 1978 |
| Anderson, Judge William Shaw, House | Austintown | Building | 1976 |
| Arlington Avenue District | Youngstown | District | 1974 |
| Austintown Log House | Youngstown | Building | 1974 |
| Baltimore & Ohio Railroad Terminal | Youngstown | Building | 1986 |
| Burt Building | Youngstown | Building | 2008 |
| Butler Institute Of American Art | Youngstown | Building | 1974 |
| Central Tower Building | Youngstown | Building | 1980 |
| City Hall Annex | Youngstown | Building | 1986 |
| Crandall Park-Fifth Avenue Historic District | Youngstown | District | 1990 |
| Damascus Grade School | Damascus | Building | 1989 |
| Erie Terminal Building-Commerce Plaza Building | Youngstown | Building | 1986 |
| Federal Building | Youngstown | Building | 1980 |
| First National Bank Building | Youngstown | Building | 1980 |
| Forest Glen Estates Historic District | Boardman Township | District | 1998 |
| Forest Lawn Memorial Park | Boardman | Site | 2018 |
| Gallagher Building | Youngstown | Building | 2014 |
| Helen Chapel | Youngstown | Building | 1986 |
| Hopewell Furnace Site | Struthers | Site | 1975 |
| Idora Park | Youngstown | District | 1993 |
| Jay's Lunch | Youngstown | Building | 1986 |
| Jones Hall, Youngstown State University | Youngstown | Building | 1984 |
| Kirtland, Jared P., House | Poland | Building | 1976 |
| Kress Building | Youngstown | Building | 1986 |
| Lake Hamilton Dam | Struthers | Structure | 1984 |
| Lanterman Mill | Youngstown | Building | 1974 |
| Legal Arts Centre | Youngstown | Building | 2024 |
| Liberty Theatre | Youngstown | Building | 1984 |
| Lowellville Railroad Station | Lowellville | Building | 1976 |
| Mahoning County Courthouse | Youngstown | Building | 1974 |
| Mahoning National Bank Building | Youngstown | Building | 1980 |
| Maple-Dell | Salem | Building | 1990 |
| Masonic Temple | Youngstown | Building | 1997 |
| McCrory Building | Youngstown | Building | 1986 |
| McGuffey, William H., Boyhood Home Site NHL | Coitsville Township | Site | 1966 |
| McKelvey-Higbee Co. Buildings | Youngstown | Building | 1986 |
| McMillan, Reuben, Free Library | Youngstown | Building | 1986 |
| Mill Creek Park Historic District | Youngstown | District | 2005 |
| Mill Creek Park Suspension Bridge | Youngstown | Structure | 1976 |
| Neff, Conrad, House | Canfield | Building | 1974 |
| Newport Village Allotment Historic District | Boardman | District | 2006 |
| Newton, Judge Eben, House | Canfield | Building | 1974 |
| Ohio One-Ohio Edison | Youngstown | Building | 1986 |
| Old Mahoning County Courthouse | Canfield | Building | 1974 |
| Our Lady of Mount Carmel Church | Youngstown | Building | 1979 |
| Peggy Ann Building | Youngstown | Building | 1986 |
| Poland Center School | Poland | Building | 1984 |
| Rayen School | Youngstown | Building | 1974 |
| Realty Building | Youngstown | Building | 1980 |
| Renner, George J., Jr., House | Youngstown | Building | 1976 |
| Republic Iron and Steel Office Building | Youngstown | Building | 1986 |
| Ruggles, Charles, House | Canfield | Building | 1975 |
| Schulte-United Building-G.C. Murphys Building | Youngstown | Building | 2024 |
| Sebring, Frank, House | Sebring | Building | 1989 |
| South Main Street District | Poland | District | 1974 |
| South Main Street District (Boundary Increase) | Poland | District | 1984 |
| Southern Park Stable | Boardman | Building | 1986 |
| St. James Episcopal Church | Boardman | Building | 1979 |
| St. John's Episcopal Church | Youngstown | Building | 2012 |
| Stambaugh Building | Youngstown | Building | 1980 |
| Stambaugh, Henry H., Memorial Auditorium | Youngstown | Building | 1984 |
| State Theater | Youngstown | Building | 1986 |
| Strouss-Hirschberg Company | Youngstown | Building | 1986 |
| Tod Homestead Cemetery Gate | Youngstown | Building | 1976 |
| Vaughn, Daniel, Homestead | Lake Milton | Building | 1980 |
| Warner Theater | Youngstown | Building | 1980 |
| Wells Building | Youngstown | Building | 1986 |
| Welsh Congregational Church | Youngstown | Building | 1986 |
| West Federal Street Young Mens Christian Association | Youngstown | Building | 2025 |
| White Bridge | Poland Village | Structure | 1983 |
| Wick Avenue Historic District | Youngstown | District | 1974 |
| Wick Avenue Historic District (Boundary Decrease) | Youngstown | District | 1980 |
| Wick Building | Youngstown | Building | 1980 |
| Wick Park Historic District | Youngstown | District | 1990 |
| Wick Park Historic District (Boundary Increase) | Youngstown | District | 2001 |
| Youngstown Foundry and Machine East Boardman Works | Youngstown | Building | 2024 |
| Youngstown Sheet and Tube Company Housing | Campbell | District | 1982 |
| YWCA Building | Youngstown | Building | 1986 |
McGuffey, William H., Boyhood Home Site NHL Coitsville Township · Site · listed 1966 
Alliance Clay Product Company Alliance · District · listed 1978 
Anderson, Judge William Shaw, House Austintown · Building · listed 1976 
Arlington Avenue District Youngstown · District · listed 1974 
Austintown Log House Youngstown · Building · listed 1974 
Baltimore & Ohio Railroad Terminal Youngstown · Building · listed 1986 
Butler Institute Of American Art Youngstown · Building · listed 1974 
Central Tower Building Youngstown · Building · listed 1980 
Erie Terminal Building-Commerce Plaza Building Youngstown · Building · listed 1986 
Helen Chapel Youngstown · Building · listed 1986