| CoID | Company | Type | Status | States Served | 24X7 Phone |
| USDB | Utah Schools for the Deaf and the Blind | PBX/PS911/Shared Tenant | A | UT | 801-710-7427 |
| USDC | U.S. District Court, Clerk's Office (Cancelled) | PBX | C | U.S. Courthouse 601 Market Street | 215-597-7704 |
| USDOI | US Department of the Interior - CANCELLED | PBX/PS911/Shared Tenant | C | DC | 480-719-8556 |
| USDOT | US Department of Transportation - CANCELLED | PBX/PS911/Shared Tenant | C | DC | 202-366-0333 |
| USEPA | United States Environmental Protection Agency (Cancelled) | VoIP | C | VA, DC | 703-347-8707 |
| USF | University of South Florida - CANCELLED | PBX/PS911/Shared Tenant | C | FL | 800-333-9873 |
| USFPS | University Of San Francisco | PBX/PS911/Shared Tenant | A | CA | 415-422-4201 |
| USGS | US Geological Survey - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | USA - Nationwide | 703-648-7036 |
| USI | US Internet Corp | VoIP Provider | A | USA | 866-728-6676 |
| USIPC | USIPCOM | VoIP Provider | A | USA - Nation Wide | 800-972-5004 |
| USIT | US In Touch (CANCELLED) | Facility | C | NV | 775-513-2831 |
| USJKV | Nestle USA Inc. | 9-1-1 Admin-CPE ALI | A | IL | 217-245-9511 |
| USLD1 | U.S. Long Distance (Cancelled) | Facility | C | USA | 800-460-1111 |
| USLEC | Windstream | CLEC Facility CLEC Reseller CLEC UNE | A | USA - Nationwide | 800-200-1989 Option 3 |
| USLK | TDS | CLEC Facility ILEC | A | MN | 888-790-1216 |
| USLKP | TDS | CLEC Facility | A | MN | 888-790-1216 |
| USLTN | US LEC/Pinpoint Platform (Cancelled) | CLEC | C | TN | 800-978-7532 |
| USNAP | SPJKSBJ, Inc. d/b/a US-NAP (CANCELLED) | CLEC Facility, Wireless/Cellular/PCS, VoIP | C | All US | 334-779-9999 |
| USNH | University System of New Hampshire | PBX/PS911/Shared Tenant | A | NH | 603-862-1427 |
| USOL | USOL Holdings, Inc. (CANCELLED) | PSP | C | TX, CO, OR, VA | 800-844-1001 |
| USP1 | USP One(Cancelled) | 9-1-1 Admin-CPE ALI | C | UT | 801-415-7182 |
| USPC | Peace Corps - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | CA | DC | GA | IL | MA | NY | TX | WA | 202-413-4116 |
| USPTO | U.S. Patent and Trademark Office (Cancelled) | PBX | C | USPTO Campus | 703-308-6667 |
| USS | United States Steel Corporation | PBX/PS911/Shared Tenant | A | AL | AR | DC | IN | MI | OH PA | TX | 412-433-1562 |
| USSP | United States Special Police (USSP) | PBX/PS911/Shared Tenant | A | DC | MD | MO | PA | VA | 202-600-4815 |
| USTC | Union Springs Telephone Co. Inc. | Facility | A | AL: Union Springs | Perote | Midway | Fort Davis | 334-738-2114 |
| USUE | Utah State University Eastern - CANCELLED | PBX/PS911/Shared Tenant | C | UT | 435-749-1481 |
| USUHS | Uniformed Services University of the Health Svc | Other - (must identify below) | PS-ALI | A | MD | 301-319-0579 |
| USUNW | US Unwired (Cancelled) | Wireless | C | TX, LA, AL, FL, MS, AR, TN | 337-310-3121 |
| USWC | Qwest (formerly US West Communications) (Cancelled) | Tel. Co. | C | AZ, CO, ID, IA, MN, MT, NE, NM, ND, OR, SD, UT, WA, WY | 800-357-0911 |
| USX | US Xchange L.L.C. - CANCELLED | CLEC Facility | C | IL | IN | MI | WI | 800-525-6775 |
| UTC | United Telephone Company | ILEC | A | TN | 800-779-2227 |
| UTCO | Union Telephone Company | ILEC | A | WI | 715-335-6301 |
| UTECH | Utah Tech University | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | UT | 435-652-7500 |
| UTEX | UTEX Communications Corp. - CANCELLED | Facility | C | TX | 281-222-6307 |
| UTFED | University of Texas - Office of Federal Relations | VoIP | A | DC | 202-955-9091 |
| UTIL | Utilimaster | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) PBX/PS911/Shared Tenant | A | IN | 574-848-2028 |
| UTMA | United Telephone Mutual Aid Corporation | Facility | A | ND | 701-256-1100 |
| UTNO | Universal Telecom LLC - CANCELLED | CLEC Reseller | PBX/PS911/Shared Tenant | VoIP Provider | C | LA | MS | 504-962-3511 |
| UTOL | University of Toledo - CANCELLED | PBX/PS911/Shared Tenant | C | OH | 419-530-2600 |
| UTS | UpCasa Technology Services - CANCELLED | VoIP Reseller | C | USA - Nationwide | 888-872-2720 |
| UUTSL | Salt Lake County - CANCELLED | PBX/PS911/Shared Tenant | C | UT | 385-468-0700 |
| UVAW | University of Virginia's College at Wise | PBX/PS911/Shared Tenant | A | | 276-328-2677 |
| UVMCV | Central Vermont Medical Center Inc. | PBX/PS911/Shared Tenant | A | VT | 802-371-4176 |
| UVOIP | UniVoIP Inc. | CLEC Reseller VoIP Provider | | USA - Nationwide | (877) 660-6677 |
| UVOX | UniVoxx | VoIP Provider | A | USA - Nationwide | 248-243-8959 |
| UVTMG | UNITEL VOICE LLC | VoIP Reseller | A | USA - Nationwide | 630-753-8718 |
| UVU | Utah Valley University | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | UT | 801-863-8000 |
| UYT | Utility Telephone Inc. | CLEC Facility | VoIP | A | ALL | 866-788-4548 |
| VACH | Vernon Advent Christian Home Inc. - CANCELLED | PBX/PS911/Shared Tenant | C | VT | 802-254-6041 |