| Port Code | Port Name | Country |
| USGOD | Godwin | United States |
| USGOE | Golden | United States |
| USGOH | Gorham | United States |
| USGOI | Genoa | United States |
| USGOK | Guthrie | United States |
| USGOL | Gold Beach | United States |
| USGOM | Gorman | United States |
| USGON | New London-Groton Apt | United States |
| USGON | Groton-New London Apt | United States |
| USGOO | Groton | United States |
| USGOP | Good Hope | United States |
| USGOR | Gordon | United States |
| USGOS | Goshen | United States |
| USGOT | Groton | United States |
| USGOU | Goulds | United States |
| USGOV | Gordonsville | United States |
| USGOY | Gregory | United States |
| USGOZ | Gonzales | United States |
| USGPB | Garfield | United States |
| USGPE | Gardners | United States |
| USGPK | Galena Park | United States |
| USGPL | Grapeland | United States |
| USGPS | Greenwell Springs | United States |
| USGPT | Gulfport | United States |
| USGPU | Gypsum | United States |
| USGPV | Grapevine | United States |
| USGPX | Glassport | United States |
| USGPZ | Grand Rapids | United States |
| USGQQ | Galion | United States |
| USGRA | Grand Portage | United States |
| USGRB | Green Bay | United States |
| USGRC | Graceville | United States |
| USGRD | Greenwood | United States |
| USGRE | Greenville | United States |
| USGRF | Grasonville | United States |
| USGRG | Gray | United States |
| USGRH | Greenwich | United States |
| USGRI | Grand Island | United States |
| USGRK | Grant Park | United States |
| USGRL | Great Lakes | United States |
| USGRM | Grand Marais | United States |
| USGRN | Greenville | United States |
| USGRO | Grove City | United States |
| USGRP | Greencastle | United States |
| USGRQ | Graham | United States |
| USGRR | Grand Rapids | United States |
| USGRS | Greensburg | United States |
| USGRT | Groveton | United States |
| USGRU | Grundy Center | United States |
| USGRV | Grays River | United States |
| USGRW | Greenwich | United States |
| USGRX | Garland | United States |
| USGRY | Gramercy | United States |
| USGRZ | Griffin | United States |
| USGSB | Goldsboro | United States |
| USGSC | Goose Creek | United States |
| USGSE | Glouster | United States |
| USGSG | Glasgow | United States |
| USGSH | Goshen | United States |
| USGSM | Geismar | United States |
| USGSN | Gaston | United States |
| USGSO | Greensboro-High Point Apt | United States |
| USGSO | High Point-Greensboro Apt | United States |
| USGSP | Greer-Greenville Apt | United States |
| USGSP | Greenville-Greer Apt | United States |
| USGSR | Glade Spring | United States |
| USGSS | Grosse Pointe | United States |
| USGST | Gustavus | United States |
| USGSU | Galesburg | United States |
| USGSV | Griswoldville | United States |
| USGSY | Gassaway | United States |
| USGSZ | Garrison | United States |
| USGTF | Great Falls | United States |
| USGTG | Grovetown | United States |
| USGTJ | Grant | United States |
| USGTL | Gretna | United States |
| USGTN | Germantown | United States |
| USGTO | Guntown | United States |
| USGTP | Green Tree | United States |
| USGTS | Greeneville | United States |
| USGTT | Gillett | United States |
| USGTU | Gladstone | United States |
| USGTV | Graniteville | United States |
| USGTW | Georgetown | United States |
| USGTY | Gettysburg | United States |
| USGTZ | Glenmont | United States |
| USGUC | Gunnison | United States |
| USGUD | Guild | United States |
| USGUE | Guntersville | United States |
| USGUF | Gulf Shores | United States |
| USGUL | Guilford | United States |
| USGUO | Gurdon | United States |
| USGUP | Gallup | United States |
| USGUR | Gurnee | United States |
| USGUS | Peru | United States |
| USGUT | Gustine | United States |
| USGUW | Guilderland Center | United States |
| USGUY | Guymon | United States |
| USGVA | Gore | United States |
| USGVD | Groveland | United States |