| Consolidated Communications Networks, Inc. | - | Dickinson, ND | Active |
| Consolidated Communications Penn Telecom | - | Mattoon, IL | Inactive |
| Consolidated Communications Telecom Services of Fo | Consolidated Communications | Mattoon, IL | Inactive |
| Contel Systems, Inc. | Contel System, Inc. | Brainerd, MN | Active |
| Conterra Ultra Broadband, LLC | - | Charlotte, NC | Active |
| Conterra Wireless Broadband, LLC. | - | Charlotte, NC | Active |
| Continental Telephone, LLC | - | WILMINGTON, DE | Inactive |
| Convergence Systems, Inc. | - | San DIego, CA | Active |
| Convergent Telesis, LLC | Hamptons Telephone | Southampton, NY | Inactive |
| Conversent Communications of Connecticut, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of Maine, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of Massachusetts, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of New Hampshire, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of New Jersey, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of New York, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of Pennsylvania, LLC | Conversent Communications, LLC. | Marlboro, MA | Inactive |
| Conversent Communications of Rhode Island, LLC | Conversent Communications | Waltham, MA | Inactive |
| Conversent Communications of Vermont, LLC | - | Waltham, MA | Inactive |
| Coon Creek Telecommunications Corp. | - | Blairstown, IA | Inactive |
| Coon Rapids Municipal Communications Utility | CRMU- Localink | Coon Rapids, IA | Active |
| Cooperative Communications, Inc. | - | Belleville, NJ | Active |
| Copa Communications llc | Copa communications llc | charleston, SC | Active |
| Cordia Communications Corp. | - | Miami, FL | Active |
| Core Communications LLC | - | North Kansas City, MO | Inactive |
| Core Communications, Inc. | CoreTel | Anderson, SC | Active |
| CoreComm ATX, Inc. | ATX Communications | King of Prussia, PA | Inactive |
| CoreComm Newco, Inc. | CoreComm | King of Prussia, PA | Inactive |
| Coretec Communications, LLC | - | Washington, IL | Inactive |
| Cornerstone Telephone Company, LLC | - | Troy, NY | Inactive |
| Corporatepage.com, Inc. | Upstate Telephone | Rochester, NY | Inactive |
| Corvus, Inc. | - | Southfield, MI | Inactive |
| Cost Plus, LLC | - | Elk Grove Village, IL | Inactive |
| Country Cable LLC | - | Spokane, WA | Active |
| Covad Communications Company | - | Santa Clara, CA | Inactive |
| Cox Arizona Telcom, L.L.C. | Cox Communications | Atlanta, GA | Inactive |
| Cox Arkansas Telecom, Inc. | Cox Communications | Atlanta, GA | Inactive |
| Cox Colorado Telcom, LLC | Cox Business Services | Atlanta, GA | Inactive |
| Cox Communications NFS, LLC | - | Atlanta, GA | Inactive |
| Cox Communications, Inc. | - | Atlanta, GA | Active |
| Cox Florida Telcom, LP | Cox Communications | Atlanta, GA | Inactive |
| Cox Georgia Telcom, LLC | Cox Communications | Atlanta, GA | Inactive |
| Cox Idaho Telecom, LLC. | Cox Communications | Atlanta, GA | Inactive |
| Cox Kansas Telcom, L.L.C. | Cox Communications | Atlanta, GA | Inactive |
| Cox Louisiana Telcom, LLC. | Cox Communications | Atlanta, GA | Inactive |
| Cox Nebraska Telcom II, L.L.C. | Cox Communications | Atlanta, GA | Inactive |
| Cox Nevada Telcom, LLC | - | Atlanta, GA | Inactive |
| Cox Ohio Telcom, LLC. | Cox Communications | Atlanta, GA | Inactive |
| Cox Oklahoma Telcom,LLC dba Cox Business Services | Cox Communications | Atlanta, GA | Inactive |
| Cox Rhode Island Telcom, LLC | Cox Communications | Atlanta, GA | Inactive |
| Cox Telcom - Florida, LP | Cox Communications | Atlanta, GA | Inactive |