- Coolfont Resort and Conference Center
- Cooper Bussmann
- Cooper Levenson
- Cooper University Health Care
- Cooperative Extension Office
- Coordinated Health System of Jefferson County
- Coosa Valley Medical Center
- Copeland Oaks
- Copper Mountain Resort
- Coral Gables Hospital
- Coram Healthcare of Gretna, Nebraska
- Coram Healthcare of Parkersburg, West Virginia
- Corazon
- Corbin Willits Systems
- Cordis Corporation
- Cordova Bolt Inc.
- Corlex International Inc.
- CorneaGen - Orlando-Medical Eye Bank of Florida
- Cornejo and Sons Inc.
- Cornell Abraxes
- Cornell Emergency Response Systems
- Cornerstone Broken Arrow
- Cornerstone Care Community Health Centers of Greensboro and Rogersville
- Cornerstone Muskogee
- Cornerstone Specialty Hospitals - Shawnee
- Corning, Inc
- Corona Regional Medical Center
- Corona-Norco United Way
- Corporal Michael J. Crescenz Medical Center
- Corporate Express
- Corporate Productions, Inc.
- Corporate Systems Group, Inc.
- Corpus Christi Padre Island Convention and Visitors Bureau
- Corrections Corporation of America
- Corry Memorial Hospital
- Corsicana-Navarro County Chamber of Commerce
- CorVel Corp.
- Coshocton County Hospital
- Costco n.° 665 Christown Spectrum Mall)
- Cottage Hospital
- Cotton Restoration Inc.
- Cottonwood Hospital
- Cottonwood Hospital Volunteer Auxiliary
- Cottonwood Ladies Club
- Council Bluffs
- Council Oak Comprehensive Healthcare
- Council of Chief State School Officers
- Council of Governments-Ogden
- Council of State Governments
- Council on Aging