| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Och'on-dong | city | Incheon | Korea, Republic of (South) | 37.81 | 126.42 | 42 | 6943 |
| Ochondong | city | Incheon | Korea, Republic of (South) | 37.81 | 126.42 | 42 | 6943 |
| Och’on-dong | city | Incheon | Korea, Republic of (South) | 37.81 | 126.42 | 42 | 6943 |
| Oeju | city | Incheon | Korea, Republic of (South) | 37.71 | 126.39 | 32 | 6686 |
| Okchuk-tong | city | Incheon | Korea, Republic of (South) | 37.84 | 124.71 | 180 | 3204 |
| Okgae | city | Incheon | Korea, Republic of (South) | 37.76 | 126.51 | 9 | 33702 |
| Okkye | city | Incheon | Korea, Republic of (South) | 37.76 | 126.51 | 9 | 33702 |
| Omi | city | Incheon | Korea, Republic of (South) | 37.81 | 126.24 | 32 | 4689 |
| Ongam | city | Incheon | Korea, Republic of (South) | 37.54 | 126.38 | 0 | 2226 |
| Ongam-ni | city | Incheon | Korea, Republic of (South) | 37.53 | 126.37 | 3 | 2139 |
| Ongil | city | Incheon | Korea, Republic of (South) | 37.66 | 126.42 | 45 | 6422 |
| Ongjakgol | city | Incheon | Korea, Republic of (South) | 37.69 | 126.45 | 324 | 9064 |
| Ongjong | city | Incheon | Korea, Republic of (South) | 37.63 | 126.68 | 39 | 178129 |
| Onisan-ni | city | Incheon | Korea, Republic of (South) | 37.66 | 126.62 | 26 | 65242 |
| Onsang | city | Incheon | Korea, Republic of (South) | 37.64 | 126.49 | 78 | 14067 |
| Onsu-ri | city | Incheon | Korea, Republic of (South) | 37.64 | 126.49 | 78 | 10473 |
| Onsugok | city | Incheon | Korea, Republic of (South) | 37.64 | 126.49 | 78 | 10473 |
| Onsui | city | Incheon | Korea, Republic of (South) | 37.64 | 126.49 | 78 | 10473 |
| Onsuiri | city | Incheon | Korea, Republic of (South) | 37.64 | 126.49 | 78 | 10473 |
| Onyang-dong | city | Incheon | Korea, Republic of (South) | 37.48 | 126.55 | 72 | 20829 |
| Oru | city | Incheon | Korea, Republic of (South) | 37.09 | 125.96 | 0 | 3688 |
| Oryu-dong | city | Incheon | Korea, Republic of (South) | 37.59 | 126.62 | 0 | 116585 |
| Oryu-dong | city | Incheon | Korea, Republic of (South) | 37.59 | 126.73 | 91 | 339041 |
| Oryu-gol | city | Incheon | Korea, Republic of (South) | 37.63 | 126.50 | 144 | 22711 |
| Oryu-ri | city | Incheon | Korea, Republic of (South) | 37.59 | 126.62 | 0 | 116585 |
| Oryunae | city | Incheon | Korea, Republic of (South) | 37.76 | 126.45 | 288 | 8373 |
| Osan | city | Incheon | Korea, Republic of (South) | 37.74 | 126.39 | 62 | 7102 |
| Osumul | city | Incheon | Korea, Republic of (South) | 37.77 | 126.41 | 36 | 8085 |