| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| OYP (ST GEORGES DE L OYAPOCK) | airport | French Guiana | 3.90 | -51.80 | 46 | 0 | |
| Oiseau Fou | city | Guyane | French Guiana | 4.89 | -53.05 | 127 | 0 |
| Ondiaye | city | Guyane | French Guiana | 5.21 | -54.31 | 91 | 1203 |
| Opoya | city | Guyane | French Guiana | 3.37 | -54.05 | 295 | 0 |
| Organabo | city | Guyane | French Guiana | 5.55 | -53.46 | 3 | 0 |
| Oscar | city | Guyane | French Guiana | 2.85 | -52.45 | 226 | 0 |
| Otily | city | Guyane | French Guiana | 5.27 | -54.26 | 72 | 130 |
| Ouanary | city | Guyane | French Guiana | 4.21 | -51.67 | 3 | 105 |
| Ouaqui | city | Guyane | French Guiana | 3.45 | -53.99 | 282 | 0 |
| Oulapa | city | Guyane | French Guiana | 5.17 | -52.65 | 3 | 19165 |
| Ouragan | city | Guyane | French Guiana | 3.93 | -52.99 | 413 | 0 |
| Oyampis | city | Guyane | French Guiana | 3.12 | -52.34 | 180 | 696 |
| Oyapock | city | Guyane | French Guiana | 3.89 | -51.80 | 68 | 7983 |