| Business | Phone |
| Bechtel Corp 5275 Westview Dr, Frederick 21703 | (301) 228-6000 |
| Central Tech Svc Inc 4907 Ridge Crest Ct, Frederick 21702 | (301) 371-9779 |
| Centurion Title Svc Inc 365 W Patrick St, Frederick 21701 | (301) 662-8758 |
| Communications Services-The Df 452 Prospect Blvd, Frederick 21701 | (301) 696-1550 |
| Cts Internet Svc & Systems 3 College Ave, Frederick 21701 | (301) 663-0080 |
| Diamond Settlement Svc Inc 178 Thomas Johnson Dr, Frederick 21702 | (301) 695-9080 |
| New Horizons Psychological Svc 65 Thomas Johnson Dr, Frederick 21702 | (301) 698-0008 |
| Maid Brigade Of Frederick 184 Thomas Johnson Dr., Suite 203l, Frederick 21702 | (877) 202-6046 |