| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Siddan | city | An Mhi | Ireland | 53.8097222 | -6.6563889 | 209 | 4334 |
| Sillagh | city | Cill Dara | Ireland | 53.1666667 | -6.6372222 | 462 | 7166 |
| Silver Ford | city | Maigh Eo | Ireland | 53.9894444 | -9.0261111 | 334 | 1851 |
| Silver Stream | city | | Ireland | 54.2666667 | -6.9166667 | 213 | 3483 |
| Silvermines | city | Tiobraid Arann | Ireland | 52.7902778 | -8.2341667 | 616 | 2846 |
| Sinclair's Village | city | Gaillimh | Ireland | 53.3011111 | -8.2647222 | 242 | 2841 |
| Sinclairʼs Village | city | Gaillimh | Ireland | 53.3011111 | -8.2647222 | 242 | 2841 |
| Single Street | city | County Donegal | Ireland | 54.4830556 | -8.2641667 | 3 | 1245 |
| Siol Ealaigh | city | Cill Mhantain | Ireland | 52.7538889 | -6.5372222 | 265 | 4573 |
| Sionainn | city | An Clar | Ireland | 52.7038889 | -8.8641667 | 0 | 3652 |
| Six Crosses | city | Ciarrai | Ireland | 52.4116667 | -9.5108333 | 298 | 2409 |
| Sixmile Bridge | city | County Limerick | Ireland | 52.5408333 | -8.545 | 249 | 5475 |
| Sixmilebridge | city | An Clar | Ireland | 52.7413889 | -8.7741667 | 141 | 2654 |
| Sixmilewater | city | Corcaigh | Ireland | 52.0113889 | -8.5638889 | 492 | 5201 |
|
|