| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Obelisco | city | Piura | Peru | -4.88 | -80.83 | 157 | 4942 |
| Obrero de Yuscay | city | Piura | Peru | -4.68 | -80.22 | 931 | 12078 |
| Ocoto Alto | city | Piura | Peru | -4.94 | -80.39 | 301 | 5771 |
| Ocoto Alto Hacienda | city | Piura | Peru | -4.94 | -80.39 | 301 | 5771 |
| Ocoto Bajo | city | Piura | Peru | -4.93 | -80.41 | 291 | 6047 |
| Ojo del Agua | city | Piura | Peru | -4.34 | -80.54 | 839 | 745 |
| Olivares | city | Piura | Peru | -5.30 | -80.65 | 98 | 4553 |
| Olivares Hacienda | city | Piura | Peru | -4.97 | -80.60 | 203 | 50551 |
| Olivares Hacienda | city | Piura | Peru | -5.30 | -80.65 | 98 | 4553 |
| Olivares de San Fernando | city | Piura | Peru | -4.97 | -80.60 | 203 | 50551 |
| Olleria | city | Piura | Peru | -6.50 | -80.00 | 380 | 7512 |
| Olleros | city | Piura | Peru | -4.71 | -79.64 | 5029 | 447 |
| Olleros Hacienda | city | Piura | Peru | -4.71 | -79.64 | 5029 | 447 |
| Ollería | city | Piura | Peru | -4.70 | -79.62 | 6013 | 447 |
| Olmito | city | Piura | Peru | -5.29 | -79.47 | 7808 | 6956 |
| Onza de Oro | city | Piura | Peru | -5.49 | -80.74 | 19 | 3013 |
| Oratanga | city | Piura | Peru | -4.64 | -80.70 | 830 | 1793 |
| Oratanga | city | Piura | Peru | -4.60 | -80.67 | 830 | 1944 |
| Orejones | city | Piura | Peru | -4.70 | -80.90 | 882 | 2238 |
| Orejuela | city | Piura | Peru | -4.64 | -79.62 | 6709 | 447 |
| Orejuela Hacienda | city | Piura | Peru | -4.64 | -79.62 | 6709 | 447 |
| Oriente | city | Piura | Peru | -4.88 | -80.68 | 223 | 38051 |
| Ornopampa | city | Piura | Peru | -5.47 | -79.74 | 1095 | 2909 |
| Ornopampa Hacienda | city | Piura | Peru | -5.47 | -79.74 | 1095 | 2909 |
| Orregos | city | Piura | Peru | -4.47 | -80.52 | 830 | 745 |
| Otoya | city | Piura | Peru | -5.21 | -79.96 | 830 | 10100 |
| Ovegeria | city | Piura | Peru | -4.88 | -80.82 | 154 | 4462 |
| Oveja | city | Piura | Peru | -4.52 | -81.17 | 278 | 8932 |
| Ovejeria | city | Piura | Peru | -4.88 | -80.82 | 154 | 4462 |
| Ovejeria Hacienda | city | Piura | Peru | -4.88 | -80.82 | 154 | 4462 |
| Overal | city | Piura | Peru | -4.33 | -80.69 | 1935 | 819 |
| Oxahuay | city | Piura | Peru | -4.55 | -79.78 | 3720 | 7256 |
| Oyocos | city | Piura | Peru | -4.35 | -80.95 | 1013 | 9288 |