| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| O'Neill's Cross Roads | city | Kildare | Ireland | 53.18 | -6.98 | 400 | 3692 |
| Oakfield | city | Kildare | Ireland | 53.21 | -6.64 | 830 | 20368 |
| Obelisks | city | Kildare | Ireland | 52.96 | -6.85 | 324 | 1644 |
| Oghill Bridge | city | Kildare | Ireland | 53.12 | -7.01 | 252 | 3034 |
| Old Kilcullen | city | Kildare | Ireland | 53.11 | -6.77 | 830 | 4327 |
| Oldcourt | city | Kildare | Ireland | 53.03 | -6.99 | 249 | 7552 |
| Oldgrange | city | Kildare | Ireland | 53.04 | -6.87 | 830 | 1734 |
| Oldtown Donore | city | Kildare | Ireland | 53.25 | -6.78 | 344 | 6434 |
| Oldtowndonore | city | Kildare | Ireland | 53.25 | -6.78 | 344 | 6434 |
| Oughterard | city | Kildare | Ireland | 53.28 | -6.56 | 830 | 10563 |
| O’Neill’s Cross Roads | city | Kildare | Ireland | 53.18 | -6.98 | 400 | 3692 |