| Town Name | Type | Region | Province / State | County | Municipality | Population | Latitude | Longitude | |
|---|---|---|---|---|---|---|---|---|---|
| O Barco | town | 11469 | 42.416191 | -6.983967 | Map | ||||
| O Campo da Feira | village | 1273 | 43.189964 | -8.472196 | Map | ||||
| O Carballiño | town | 11062 | 42.430084 | -8.078119 | Map | ||||
| O Grove | town | 7403 | 42.495300 | -8.864090 | Map | ||||
| O Porriño | town | 5656 | 42.161880 | -8.620268 | Map | ||||
| O Rosal | town | 6531 | 41.936993 | -8.837036 | Map | ||||
| O Seixo | village | 1114 | 41.992359 | -8.742965 | Map | ||||
| Ocaña | town | Castilla-La Mancha | Toledo | 10098 | 39.958561 | -3.499924 | Map | ||
| Òdena | village | 1524 | 41.606880 | 1.642221 | Map | ||||
| Ogíjares | town | 13403 | 37.118813 | -3.609129 | Map | ||||
| Ojén | village | 2949 | 36.563850 | -4.855721 | Map | ||||
| Olakueta | village | Euskadi | Bizkaia | 4066 | 43.169666 | -2.575329 | Map | ||
| Olesa de Montserrat | town | 23646 | 41.543053 | 1.893187 | Map | ||||
| Oliana | village | 1843 | 42.067162 | 1.314942 | Map | ||||
| Olías del Rey | village | Castilla-La Mancha | Toledo | 7175 | 39.944736 | -3.987252 | Map | ||
| Olite | village | 3722 | 42.481083 | -1.651575 | Map | ||||
| Oliva | town | 23726 | 38.920200 | -0.120974 | Map | ||||
| Oliva de la Frontera | village | Extremadura | Badajoz | 5573 | 38.276699 | -6.918071 | Map | ||
| Oliva de Mérida | village | 1844 | 38.789951 | -6.124346 | Map | ||||
| Olivares | village | 9534 | 37.416710 | -6.156429 | Map | ||||
| Olivares | village | 1038 | 37.331921 | -3.765099 | Map | ||||
| Olivenza | town | Extremadura | Badajoz | 12008 | 38.684475 | -7.100566 | Map | ||
| Olmedo | village | 3885 | 41.287098 | -4.686690 | Map | ||||
| Olocau | town | 1482 | 39.700676 | -0.531206 | Map | ||||
| Olost | village | 1037 | 41.985294 | 2.094162 | Map |