| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Jack White's Cross Roads | city | Wicklow | Ireland | 52.88 | -6.10 | 127 | 1395 |
| Jack White’s Cross Roads | city | Wicklow | Ireland | 52.88 | -6.10 | 127 | 1395 |
| Jackson's Bridge | city | Kildare | Ireland | 53.38 | -6.62 | 246 | 12194 |
| Jackson’s Bridge | city | Kildare | Ireland | 53.38 | -6.62 | 246 | 12194 |
| Jackstown | city | Donegal | Ireland | 55.03 | -8.27 | 3 | 2310 |
| Jamestown | city | Ireland | 53.93 | -8.03 | 223 | 2598 | |
| Jamestown | city | Kilkenny | Ireland | 52.37 | -7.02 | 111 | 1798 |
| Jamestown | city | Kilkenny | Ireland | 52.38 | -7.31 | 164 | 2643 |
| Jamestown | city | Ireland | 52.53 | -7.48 | 288 | 1816 | |
| Jamestown | city | Laois | Ireland | 53.12 | -7.11 | 259 | 3618 |
| Jamestown | city | Meath | Ireland | 53.65 | -6.84 | 259 | 2213 |
| Jeffrystown | city | An Iarmhi | Ireland | 53.59 | -7.21 | 830 | 1234 |
| Jenkinstown | city | Kilkenny | Ireland | 52.72 | -7.28 | 229 | 3294 |
| Jenkinstown Cross | city | Lu | Ireland | 54.02 | -6.31 | 0 | 2502 |
| Joanstown | city | Ireland | 52.33 | -7.44 | 219 | 5573 | |
| John's Bridge | city | Cork | Ireland | 52.24 | -8.89 | 830 | 1981 |
| Johnduffswood | city | Carlow | Ireland | 52.75 | -7.03 | 830 | 1659 |
| Johnstons Bridge | city | Leitrim | Ireland | 53.83 | -7.87 | 219 | 1529 |
| Johnstown | city | Meath | Ireland | 53.41 | -6.84 | 282 | 2803 |
| Johnstown | city | Kildare | Ireland | 53.24 | -6.62 | 830 | 16478 |
| Johnstown | city | Wexford | Ireland | 52.78 | -6.23 | 246 | 1964 |
| Johnstown | city | Kilkenny | Ireland | 52.75 | -7.55 | 830 | 2354 |
| Johnstown | city | Cork | Ireland | 51.82 | -9.09 | 830 | 1103 |
| Johnstown | city | Wexford | Ireland | 52.24 | -6.68 | 13 | 1823 |
| Johnstown | city | Wexford | Ireland | 52.69 | -6.64 | 288 | 2989 |
| Johnstown | city | Wicklow | Ireland | 52.83 | -6.13 | 19 | 8948 |
| Johnstown | city | Wicklow | Ireland | 53.09 | -6.56 | 882 | 1771 |
| Johnstown | city | An Iarmhi | Ireland | 53.60 | -7.17 | 830 | 1484 |
| Johnstown | city | An Iarmhi | Ireland | 53.65 | -7.18 | 830 | 1394 |
| Johnstown | city | Meath | Ireland | 53.68 | -6.98 | 324 | 1658 |
| Johnstown | city | Meath | Ireland | 53.64 | -6.65 | 209 | 16194 |
| Johnstown Bridge | city | Kildare | Ireland | 53.40 | -6.86 | 285 | 2798 |
| Johnstown North | city | Kildare | Ireland | 52.91 | -6.90 | 236 | 6747 |
| Johnstown South | city | Kildare | Ireland | 52.90 | -6.88 | 239 | 7579 |
| Johnstownbridge | city | Leitrim | Ireland | 53.83 | -7.87 | 219 | 1529 |
| Johnswell | city | Kilkenny | Ireland | 52.70 | -7.17 | 830 | 2936 |
| John’s Bridge | city | Cork | Ireland | 52.24 | -8.89 | 830 | 1981 |
| Jonestown Cross Roads | city | Offaly | Ireland | 53.35 | -7.06 | 337 | 6193 |
| Jordan's Bridge | city | Cork | Ireland | 52.08 | -8.63 | 403 | 5347 |
| Jordanstown | city | Meath | Ireland | 53.66 | -6.80 | 242 | 2389 |
| Jordanstown | city | Meath | Ireland | 53.59 | -6.62 | 360 | 5594 |
| Jordan’s Bridge | city | Cork | Ireland | 52.08 | -8.63 | 403 | 5347 |
| Joristown Lower | city | An Iarmhi | Ireland | 53.54 | -7.12 | 396 | 2037 |
| Joristown Upper | city | An Iarmhi | Ireland | 53.53 | -7.11 | 387 | 2016 |
| Judgeville | city | An Iarmhi | Ireland | 53.35 | -7.38 | 393 | 1009 |
| Julianstown | city | Meath | Ireland | 53.68 | -6.32 | 3 | 26054 |