| 1 | GRM | Arizona State Gobernment, Cochise County Sheriff's Office | Callsign: Geronimo, | USA | AVCODES |
| 2 | GRM | GROOME TRANSPORTATION INCORPORATED | | | SCAC4 |
| 3 | GRMC | GRANITE & MARBLE COUNTERTOP CO | | | SCAC4 |
| 4 | GRME | GRAND RAPIDS MTR EXP INC | | | PWRC |
| 5 | GRMG | GRAEBEL MOVING AND WAREHOUSE CORP | | | SCAC4 |
| 6 | GRMH | GRO MASTER INC | | | SCAC4 |
| 7 | GRMI | GRMI | | | SCAC4 |
| 8 | GRMN | GORMAN BROS INC | | | SCAC4 |
| 9 | GRMP | GRONDIN, M R INC | | | SCAC4 |
| 10 | GRMQ | GONZALEZ RAMIREZ, ROGELIO | | | SCAC4 |
| 11 | GRMR | GRIM, ROBERT WELDING CO INC | | | SCAC4 |
| 12 | GRMS | GRECOMAR SHIPPING AGENCY LTD | | | SCAC4 |
| 13 | GRMU | GOODRICH MARITIME PRIVATE LIMITED | | IND | BIC |
| 14 | GRMU | GOODRICH MARITIME PRIVATE LIMITED | | | SCAC4 |
| 15 | GRMW | GRISWOLD, M. W | | | SCAC1 |
| 16 | GRMW | GERBER, RALPH | | | SCAC4 |
| 17 | GRMX | The Gopher State Railway Museum Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 18 | GRMX | General Roofing Manufacturing Co. (Certain-teed Products Corp.) | 8/1920 | | NAKINA |
| 19 | GRMX | The Gopher State Railway Museum Inc. | Jul-00 | | NRHS |
| 20 | GRMX | *CERTAIN-TEED PRODUCTS CORP. [GENERAL ROOFING MANUFACTURING CO.] | | | PWRC |
| 21 | GRMX | *GREAT MIAMI & WESTERN RAILWAY | | | PWRC |
| 22 | GRMX | +GOPHER STATE RAILWAY MUSEUM | | | PWRC |
| 23 | GRMX | Gopher State Railway Museum | | | RSRV |
| 24 | GRMX | GOPHER STATE RAILWAY MUSEUM INC, TH | | | SCAC4 |
| 25 | GRMY | GRIMES TRUCKING SERVICES INC | | | SCAC4 |
