| 1 | WDC | Washington Metropolitan Area Transit Authority | City: Washington DC | US-DC | TRAFFIC |
| 2 | WDCC | WEBSTER, DON COMPANY INC, THE | | | SCAC4 |
| 3 | WDCH | WOOD, CHAS & SON MOVING INC | | | SCAC4 |
| 4 | WDCM | WOOD FARMS | | | SCAC4 |
| 5 | WDCN | WARD DISTRIBUTING COMPANY INC | | | SCAC4 |
| 6 | WDCP | WAYNE-DALTON CORP | | | SCAC4 |
| 7 | WDCQ | WORLDWIDE CONTAINER TRANSPORT INC | | | SCAC4 |
| 8 | WDCX | Wm. Davies Co., Inc. | 8/1920-7/1932 | | NAKINA |
| 9 | WDCX | Wm. Davies Co., Inc. (Canada Packers Ltd.) | 7/1935 | | NAKINA |
| 10 | WDCX | Warren-Douglas Chemical Co., Inc. | added 10/1964; 7/1965-4/1970; eliminated 11/1973 | | NAKINA |
| 11 | WDCX | Warren-Douglas Chemical Co., Inc. | Apr-70 | | NRHS |
| 12 | WDCX | Warren-Douglas Chemical Co., Inc. | 7/65-10/66; eliminated 11/73 | | NRHS |
| 13 | WDCX | *WM. DAVIES CO., INC. | | | PWRC |
| 14 | WDCX | *WARREN-DOUGLAS CHEMICAL CO., INC. | | | PWRC |
| 15 | WDCY | WORLDWIDE DELIVERY CORP | | | SCAC4 |
