| Allied Rubber & Mice | Cleveland | OH |
| Allied Services | Marietta | OH |
| Allied Signal | Fostoria | OH |
| Allis Chalmers | Norwood | OH |
| Allis Chalmers | Cincinnati | OH |
| Allis Chalmers | Cleveland | OH |
| Alloy Cast Steel | Marion | OH |
| Alloy Engineering | Berea | OH |
| Alloy Industry | Berea | OH |
| Alloys & Chemical Manufacturing | Cleveland | OH |
| All Shapes Steel Products | Warren | OH |
| Allsteel | Cleveland | OH |
| Alms & Doepke Dry Goods | Cincinnati | OH |
| Alpha Portland Cement | Ironton | OH |
| Altivity Packaging | Middletown | OH |
| Alton | Cleveland | OH |
| Aluminum Billets | Niles | OH |
| Aluminum Magnesium (WHW) | Sandusky | OH |
| Aluminum Smelting & Refining | Maple Heights | OH |
| Aluminum Smelting & Refining | Cleveland | OH |
| Alumiwal | Gnadenhutten | OH |
| Amac Enterprises | Cleveland | OH |
| Amax Specialty | Cleveland | OH |
| Ambler | Toledo | OH |
| A.M. Byers | Girard | OH |
| Amcast Industrial | Ironton | OH |
| Amcodyne | Lorain | OH |
| American Art Works | Coshocton | OH |
| American Ball Bearing | Cleveland | OH |
| American Bitumals & Asphalt | North Bend | OH |
| American Bitumals & Asphalt | Cincinnati | OH |
| American Bitumals & Asphalt | Belpre | OH |
| American Book | Cincinnati | OH |
| American Bottle | Newark | OH |
| American Box Board | Cleveland | OH |
| American Brake Shoe | Elyria | OH |
| American Brazing | Willoughby | OH |
| American Bridge | Lorain | OH |
| American Can | Toledo | OH |
| American Cancer Society | Dover | OH |
| American Cereal | Akron | OH |
| American Clay Machinery | Bucyrus | OH |
| American Coating Mills | Middletown | OH |
| American Cook | Cincinnati | OH |
| American Crayon | Sandusky | OH |
| American Cyanamid | Hamilton | OH |
| American Cyanamid | Marietta | OH |
| American Diamalt | Cincinnati | OH |
| American Electric Power | Conesville | OH |
| American Electric Power | Cheshire | OH |
