| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Oghil | city | Gaillimh | Ireland | 53.1363889 | -9.6980556 | 141 | 562 |
| Oghil | city | Gaillimh | Ireland | 53.2477778 | -8.1830556 | 242 | 2863 |
| Oldstreet | city | Gaillimh | Ireland | 53.1444444 | -8.2241667 | 282 | 2844 |
| Onaght | city | Gaillimh | Ireland | 53.1513889 | -9.79 | 226 | 506 |
| Oran Mor | city | Gaillimh | Ireland | 53.2683333 | -8.92 | 22 | 2530 |
| Oranmore | city | Gaillimh | Ireland | 53.2683333 | -8.92 | 22 | 2530 |
| Ormond View | city | Gaillimh | Ireland | 53.15 | -8.2 | 219 | 2771 |
| Oughterard | city | Gaillimh | Ireland | 53.4166667 | -9.3333333 | 203 | 1695 |
| Oultort | city | Gaillimh | Ireland | 53.0988889 | -8.2686111 | 324 | 2381 |
| Ourtnagapple | city | Gaillimh | Ireland | 53.1280556 | -9.7380556 | 3 | 643 |
| Owenbristy | city | Gaillimh | Ireland | 53.1513889 | -8.8452778 | 75 | 2885 |
| Ower | city | Gaillimh | Ireland | 53.3844444 | -9.1727778 | 85 | 2345 |
| Oxgrove Bridge | city | Gaillimh | Ireland | 53.1841667 | -8.2980556 | 344 | 2884 |
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