| Buckeye Power | Brilliant | OH |
| Buckeye Rolling Mill | Newark | OH |
| Buckeye Rubber Products | Cleveland | OH |
| Buckeye Steel | Jackson | OH |
| Buckeye Steel | Columbus | OH |
| Buckeye Sugar | Ottawa | OH |
| Bucyrus Blades | Bucyrus | OH |
| Bucyrus Electric Light | Bucyrus | OH |
| Buel Gatterdam | Columbus | OH |
| Buffalo Springfield Road Roller | Springfield | OH |
| Bulk Mail | Cincinnati | OH |
| Bullock Electric Manufacturing | Cincinnati | OH |
| Bullock Works | Norwood | OH |
| Bunker Hill Greenhouses | Medina | OH |
| Bunting Brass & Bronze | Toledo | OH |
| Burdett Oxygen | New Philadelphia | OH |
| Burdett Oxygen | Cleveland | OH |
| Burdett Oxygen | Mansfield | OH |
| Burdett Oxygen | Youngstown | OH |
| Burger Brewery | Cincinnati | OH |
| Burger Chef | Dayton | OH |
| Burgess Steel & Iron | Portsmouth | OH |
| Burke Golf | Newark | OH |
| Burns Cold Forge | Minerva | OH |
| Burns Incorportion | Lorain | OH |
| Burton Elementary School | Burton | OH |
| Bushey Cotton | Columbus | OH |
| Butler County Administration Building | Hamilton | OH |
| Butler County Jail | Cincinnati | OH |
| Butler County Retarded Children's School | Hamilton | OH |
| Butler County Vocational School | Fairfield | OH |
| ByerLite Asphalt | Cleveland | OH |
| ByerLite Asphalt | Marietta | OH |
| Cabot | Ashtabula | OH |
| Cabot | Cleveland | OH |
| Calhio Chemical | Perry | OH |
| Calhio Chemical | Cleveland | OH |
| Calhoun Residence Hall Plbg | Evendale | OH |
| C.A. Litzler | Cleveland | OH |
| Cambria Clay Products | Lorain | OH |
| Cambria Clay Products | Oak Hill | OH |
| Cambridge Brewing | Cambridge | OH |
| Cambridge Developmental Center | Claysville | OH |
| Cambridge Glass | Cambridge | OH |
| Cambridge State Hospital | Canton | OH |
| Cambridge State Hospital | Cambridge | OH |
| Campbell Soup | Napoleon | OH |
| Camp & Thompson | Cuyahoga Falls | OH |
| Canaan Coal | Canaanville | OH |
| Canadian Copper | Cleveland | OH |
