| 4901 | GRLA | GROUPE LAFRANCE | | | SCAC4 |
| 4902 | GRLA | Greenville & Lafayette IBOA | | USA | TRAFFIC |
| 4903 | GRLE | GREAT LAKE EXPRESS CO | | | PWRC |
| 4904 | GRLE | GREENLAND EQUIPMENT LTD | | | SCAC4 |
| 4905 | GRLL | GREELEYS OIL CO INC | | | SCAC4 |
| 4906 | GRLQ | GREENLINE TRANSPORTATION LLC | | | SCAC4 |
| 4907 | GRLR | GUTIERREZ LOREDO, TOMAS | | | SCAC4 |
| 4908 | GRLS | GREAT LAND | | | SCAC4 |
| 4909 | GRLT | GREAT LAKES TRANSPORTATION INC | | | SCAC4 |
| 4910 | GRLU | GRUBER GMBH & CO.KG | | D | BIC |
| 4911 | GRLU | GRUBER GMBH & CO KG | | | SCAC4 |
| 4912 | GRLV | GRS LOGISTICS INC | | | SCAC4 |
| 4913 | GRLW | GREENVILLE & WESTERN RAILWAY CO., LLC | | | PWRC |
| 4914 | GRLW | Greenville & Western Railway (Western Carolina Railway Service Corporation) | | | RSRV |
| 4915 | GRLW | GREENVILLE & WESTERN RAILWAY COMPAN | | | SCAC4 |
| 4916 | GRLZ | GRAIN LAND COOP | | | PWRC |
| 4917 | GRM | Arizona State Gobernment, Cochise County Sheriff's Office | Callsign: Geronimo, | USA | AVCODES |
| 4918 | GRM | GROOME TRANSPORTATION INCORPORATED | | | SCAC4 |
| 4919 | GRMC | GRANITE & MARBLE COUNTERTOP CO | | | SCAC4 |
| 4920 | GRME | GRAND RAPIDS MTR EXP INC | | | PWRC |
| 4921 | GRMG | GRAEBEL MOVING AND WAREHOUSE CORP | | | SCAC4 |
| 4922 | GRMH | GRO MASTER INC | | | SCAC4 |
| 4923 | GRMI | GRMI | | | SCAC4 |
| 4924 | GRMN | GORMAN BROS INC | | | SCAC4 |
| 4925 | GRMP | GRONDIN, M R INC | | | SCAC4 |
| 4926 | GRMQ | GONZALEZ RAMIREZ, ROGELIO | | | SCAC4 |
| 4927 | GRMR | GRIM, ROBERT WELDING CO INC | | | SCAC4 |
| 4928 | GRMS | GRECOMAR SHIPPING AGENCY LTD | | | SCAC4 |
| 4929 | GRMU | GOODRICH MARITIME PRIVATE LIMITED | | IND | BIC |
| 4930 | GRMU | GOODRICH MARITIME PRIVATE LIMITED | | | SCAC4 |
| 4931 | GRMW | GRISWOLD, M. W | | | SCAC1 |
| 4932 | GRMW | GERBER, RALPH | | | SCAC4 |
| 4933 | GRMX | The Gopher State Railway Museum Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 4934 | GRMX | General Roofing Manufacturing Co. (Certain-teed Products Corp.) | 8/1920 | | NAKINA |
| 4935 | GRMX | The Gopher State Railway Museum Inc. | Jul-00 | | NRHS |
| 4936 | GRMX | *CERTAIN-TEED PRODUCTS CORP. [GENERAL ROOFING MANUFACTURING CO.] | | | PWRC |
| 4937 | GRMX | *GREAT MIAMI & WESTERN RAILWAY | | | PWRC |
| 4938 | GRMX | +GOPHER STATE RAILWAY MUSEUM | | | PWRC |
| 4939 | GRMX | Gopher State Railway Museum | | | RSRV |
| 4940 | GRMX | GOPHER STATE RAILWAY MUSEUM INC, TH | | | SCAC4 |
| 4941 | GRMY | GRIMES TRUCKING SERVICES INC | | | SCAC4 |
| 4942 | GRN | Edelweiss Holdings, Inc. d/b/a Rio Grande Air | IATA: E2, Callsign: Grande, IATA designator changed from 1I | USA | AVCODES |
| 4943 | GRN | Edelweiss Holdings, Inc. d/b/a Rio Grande Air | IATA: H7, IATA designator changed to E2* | USA | AVCODES |
| 4944 | GRN | Greenair | IATA: WK, | TR | AVCODES |
| 4945 | GRN | Grande Aviation, LLC | Callsign: Grande, | USA | AVCODES |
| 4946 | GRN | Rio Grande Air | IATA: E2 | | ICAO1 |
| 4947 | GRN | Pinsly R.R. Co. | eliminated 4/1997 | | NAKINA |
| 4948 | GRN | Carolina Piedmont Division, South Carolina Central R.R. Co., Inc. | added 7/1997; 7/2000; eliminated 10/2000; 7/2005 (not listed) | | NAKINA |
| 4949 | GRN | Greenville & Northern Ry. Co., Inc. | 1/1975; added 4/1975; 1/1980-1/1994; eliminated 7/1997 | | NAKINA |
| 4950 | GRN | Greenville & Northern Ry. Co., Inc. | 1/75; added 4/75; 1/80-1/94; eliminated 7/97 | | NRHS |
| 4951 | GRN | Pinsly R.R. Co. | eliminated 4/97 | | NRHS |
| 4952 | GRN | Carolina Piedmont Division, South Carolina Central R.R. Co., Inc. | added 7/97; 7/2000; eliminated 10/2000 | | NRHS |
| 4953 | GRN | CAROLINA PIEDMONT DIV., SOUTH CAROLINA CENTRAL RAILROAD [PINSLY RAILROAD CO.; GREENVILLE & NORTHERN RAILWAY COMPANY] | | | PWRC |
| 4954 | GRN | Greenville and Northern Railway | | | RSRV |
| 4955 | GRN | Greenville & Northern Ry. Co., Inc. | | USA | TRAFFIC |
| 4956 | GRNA | GRAINSTOVES INC | | | SCAC4 |
| 4957 | GRNC | GREENE TRANSPORT CO | | | SCAC4 |
| 4958 | GRNE | GARNER TRANSPORTATION INC | | | SCAC4 |
| 4959 | GRNF | GRAND MAYFLOWER LLC | | | SCAC4 |
| 4960 | GRNG | GRANGE SUPPLY CO INC | | | SCAC4 |
| 4961 | GRNJ | GREEN, ARTHUR | | | SCAC4 |
| 4962 | GRNK | GRANT TRUCKING | | | SCAC4 |
| 4963 | GRNL | GRANE TRANSPORTATION LINES, LTD | | | SCAC1 |
| 4964 | GRNL | GRANE TRANSPORTATION LINES LTD | | | SCAC4 |
| 4965 | GRNM | GARZA RODRIGUEZ, NOE MARIO | | | SCAC4 |
| 4966 | GRNN | GRENON, E W & SON INC | | | SCAC4 |
| 4967 | GRNR | The Grand River Ry. Co. | 1/1975-7/2005 | | NAKINA |
| 4968 | GRNR | The Grand River Ry. Co. | 1/75-7/2000 | | NRHS |
| 4969 | GRNR | CP RAIL [GRAND RIVER RY.] | | | PWRC |
| 4970 | GRNR | Grand River Railway | | | RSRV |
| 4971 | GRNR | GRAND RIVER RAILWAY COMPANY, THE | | | SCAC4 |
| 4972 | GRNS | GRAND SLAM TRUCKING INC | | | SCAC4 |
| 4973 | GRNV | GREENEVILLE OIL & PETROLEUM INC | | | SCAC4 |
| 4974 | GRNW | Great Northwest R.R. Inc. | 7/2005; added 4/2008 | | NAKINA |
| 4975 | GRNW | GREAT NORTHWEST RAILROAD | | | PWRC |
| 4976 | GRNW | Great Northwest Railroad | | | RSRV |
| 4977 | GRNW | GREAT NORTHWEST RAILROAD INC | | | SCAC4 |
| 4978 | GRNY | GREENBERG, MORRIS & CO INC | | | SCAC4 |
| 4979 | GRO | Lineas Aereas Allegro, S.A. de C.V. | IATA: LL, Callsign: Allegro, IATA Prefix: 902, Founded in 1992. Ceased operations during 2004. | MEX | AVCODES |
| 4980 | GRO | Allegro | IATA: LL | | ICAO1 |
| 4981 | GRO | Lineas Aéreas Allegro | | MEX | TRAFFIC |
| 4982 | GROD | PKS Grodzisk Mazowiecki | | PL | TRAFFIC |
| 4983 | GRODNO | | City: Grodno | BY | TRAFFIC |
| 4984 | GROEGER | Groeger Reisen GmbH | | D | TRAFFIC |
| 4985 | GROF | GROE FARM | | | SCAC4 |
| 4986 | GROG | GR Omnibus GmbH | | D | TRAFFIC |
| 4987 | GROI | Genessee Rail-One Inc. | 7/2005 | | NAKINA |
| 4988 | GROI | GENESEE RAIL-ONE, INC. | | | PWRC |
| 4989 | GROI | Genesee Rail-One | | | RSRV |
| 4990 | GROK | GROSHELL TRANSPORTATION SERVICES IN | | | SCAC4 |
| 4991 | GROL | GAROL TRANSPORTATION INC | | | SCAC4 |
| 4992 | GRON | GRANT TRANSPORT | | | SCAC4 |
| 4993 | GROP | GROWERS TRANSPORT LLC | | | SCAC4 |
| 4994 | GROQ | GN ROY | | | SCAC4 |
| 4995 | GROR | GROSS, RONALD INC | | | SCAC4 |
| 4996 | GROS | GRAVOIS COAL COMPANY | | | SCAC4 |
| 4997 | GROT | GROSHELL TRANSPORTATION SERVICES IN | | | SCAC4 |
| 4998 | GROU | BOX2HOME | | F | BIC |
| 4999 | GROV | S.J. Groves & Sons | | USA | TRAFFIC |
| 5000 | GROX | First Union Rail | added 10/1996; 7/2000-7/2005 | | NAKINA |
