- Miles-McClellan
- MillCraft Group
- Millennium Hotel Cincinnati
- Montgomery County
- Morrow County
- Morrow County Hospital
- Mosaic LTD
- Mount Carmel East
- Mount Carmel Grove City
- Mount Carmel New Albany
- Mount Carmel St. Ann's
- Mount Carmel West
- National Association of Local Boards of Health
- National Association of Sports Commissions
- National City Bank
- National Ground Water Association
- Nationwide Children's Hospital
- Nationwide Insurance
- Nationwide Retirement Solutions
- NCR
- Neace Lukens
- Neighborhood Health Care, Inc.
- NEOUCOM
- Nestle USA-Prepared Foods Co.
- New Bremen Rotary
- New Horizons Clinical Research
- Nida Lighting
- Norplas
- Northside Medical Center
- Ohio Chinese American Professional Association
- Ohio Department of Education
- Ohio Department of Health
- Ohio Department of Transportation
- Ohio Dept. of Public Safety
- Ohio Dominican University
- Ohio Grand Council of Royal and Select Masons
- Ohio Grocers Association
- Ohio Historical Society
- Ohio Hospital Association
- Ohio Northern University
- Ohio Primary Care Association
- Ohio Rehabilitation Services Commission
- Ohio Society of Association Executives
- Ohio State University Medical Center -Managed Care
- Ohio State University Wexner Medical Center
- Ohio Trucking Association
- Ohio University
- Ohio University Inn, Athens
- Ohio University Zanesville
- Ohio Valley Tissue and Skin Center