| 441 | Delve Underground | Vancouver |
| 442 | Design Works Engineering Ltd. | Regina |
| 443 | DesignPoint Engineering & Surveying Ltd. | Bedford |
| 444 | Development Engineering (London) Limited | London |
| 445 | Development Engineering (London) Limited | Paris |
| 446 | DGH Engineering Ltd. | St. Andrews |
| 447 | DIALOG | Calgary |
| 448 | DIALOG | Edmonton |
| 449 | DIALOG | Toronto |
| 450 | DIALOG | Vancouver |
| 451 | Dillon Consulting Limited | Calgary |
| 452 | Dillon Consulting Limited | Chatham |
| 453 | Dillon Consulting Limited | Edmonton |
| 454 | Dillon Consulting Limited | Fredericton |
| 455 | Dillon Consulting Limited | Guelph |
| 456 | Dillon Consulting Limited | Halifax |
| 457 | Dillon Consulting Limited | Halifax |
| 458 | Dillon Consulting Limited | Hamilton |
| 459 | Dillon Consulting Limited | Kingston |
| 460 | Dillon Consulting Limited | Kitchener |
