| Crockett Telephone Co. Inc. | Crockett Telephone Co., Inc. | Jackson, MS | Active |
| Cross Tel. Co. | Cross Telephone Company, Inc. | Warner, OK | Active |
| Crossville Tel. Co. | Crossville Telephone Company, Inc. | Crossville, IL | Active |
| Crown Point Tel. Corp. | Crown Point Telephone Corporation | Crown Point, NY | Active |
| Cuba City Tel. Exch. Co. Inc. | Cuba City Telephone Exchange Company | Cuba City, WI | Active |
| Cumberland Telephone Co. | Cumberland Telephone Company | Cumberland, IA | Active |
| Cumby Tel. Coop. Inc. | Cumby Telephone Cooperative, Inc. | Cumby, TX | Active |
| Cunningham Telephone Company, Inc. | - | Glen Elder, KS | Active |
| Custer Tel. Coop. Inc. | Custer Telephone Cooperative, Inc. | Challis, ID | Active |
| Dakota Central Telecom I, Inc. | - | Carrington, ND | Active |
| Dakota Central Telecommunications Cooperative | Dakota Central Telecommunications Cooperative, Inc | Carrington, ND | Active |
| Dalton Tel. Co. | Dalton Telephone Company | Colorado City, CO | Active |
| Danville Mutual Tel. Co. | Danville Mutual Telephone Company | Danville, IA | Active |
| Darien Tel. Co. Inc. | Darien Telephone Company, Inc. | Darien, GA | Active |
| Daviess-Martin County Rural Tel. Corp. | RTC Communications | Montgomery, IN | Active |
| DeKalb Telephone Cooperative | - | Alexandria, TN | Active |
| Decatur Tel. Co. Inc. | Decatur Telephone Company, Inc. | Decatur, MS | Active |
| Decatur Telephone Company | - | Seneca, MO | Active |
| Defiance Tel. Co. | Defiance Telephone Company, Inc. | Harlan, IA | Inactive |
| Delavan Tel. Co. | Delavan Telephone Company | Blue Earth, MN | Inactive |
| Delcambre Tel. Co. | Delcambre Telephone Company, Inc. | Delcambre, LA | Active |
| Delhi Tel. Co. | Delhi Telephone Company | Delhi, NY | Active |
| Dell Telephone Co-op., Inc. | Dell Telephone Cooperative, Inc. | Dell City, TX | Active |
| Delta County Tele-Comm, Inc. | TDS Telecom | Madison, WI | Active |
| Delta Tel. Co. Inc. | Delta Telephone Co., Inc. | Louise, MS | Inactive |
| Deposit Telephone Co. | TDS Telecom | Madison, WI | Active |
| Dickey Rural Access, Inc. | - | Ellendale, ND | Inactive |
| Dickey Rural Communications, Inc. | - | Ellendale, ND | Inactive |
| Dickey Rural Telephone Cooperative | - | Ellendale, ND | Active |
| Dickeyville Tel. Corp. | Dickeyville Telephone Corporation | Madison, WI | Active |
| Diller Tel. Co. | Diller Telephone Company | Diller, NE | Active |
| Direct Communications Ceder Valley, LLC. | - | Rockland, ID | Active |
| Direct Communications Rockland, Inc. | - | Rockland, ID | Active |
| Dixon Acquisition LLC | Central Scott Telephone | Eldridge, IA | Active |
| Dixon Telephone Company | - | Dixon, IA | Inactive |
| Dixville Tel. Co. | Dixville Telephone Company | Seekonk, MA | Active |
| Dobson Tel. Co. | Dobson Telephone Company, Inc. | Oklahoma City, OK | Active |
| Doylestown Tel. Co. | Doylestown Telephone Company | Doylestown, OH | Active |
| Drenthe Telephone Company | - | Houston, MN | Inactive |
| Dubois Tel. Exch. Inc. | Dubois Telephone Exchange, Inc. | Dubois, WY | Active |
| Ducor Telephone Company | Varcomm | Avondale, AZ | Active |
| Dumont Tel. Co. | Dumont Telephone Company | Dumont, IA | Active |
| Dunbarton Telephone Co., Inc. | Dunbarton Telephone Company, Inc. | Dunbarton, NH | Active |
| Dunkerton Telephone Cooperative | - | Dunkerton, IA | Active |
| Dunkirk & Fredonia Telephone Company | - | Fredonia, NY | Active |
| Dunnell Tel. Co. | Dunnell Telephone Company | Judson, TX | Active |
| Duo County Tel. Coop. Corp., Inc. | - | Jamestown, KY | Active |
| E. Ritter Telephone Company | - | Jonesboro, AR | Active |
| ENMR Plateau Telephone Cooperative-TX | ENMR - Plateau Telecommunications, Inc | Clovis, NM | Active |
| ETS Telephone Company, Inc. | ETS Telephone Company | Houston, TX | Active |