| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Saint Catherines | city | Donegal | Ireland | 54.62 | -8.46 | 3 | 2224 |
| Saint Johnston | city | Donegal | Ireland | 54.93 | -7.45 | 3 | 3624 |
| Saint Johnstown | city | Donegal | Ireland | 54.93 | -7.45 | 3 | 3624 |
| Sallybrook | city | Donegal | Ireland | 54.96 | -7.57 | 308 | 1884 |
| Sandfield | city | Donegal | Ireland | 54.80 | -8.45 | 3 | 912 |
| Seacor | city | Donegal | Ireland | 54.94 | -7.90 | 259 | 644 |
| Seedagh | city | Donegal | Ireland | 55.19 | -7.73 | 0 | 1297 |
| Sessiagh | city | Donegal | Ireland | 55.24 | -7.74 | 82 | 765 |
| Shallogan | city | Donegal | Ireland | 54.84 | -8.22 | 882 | 515 |
| Shalwy | city | Donegal | Ireland | 54.62 | -8.53 | 0 | 847 |
| Shanaghan | city | Donegal | Ireland | 54.77 | -8.45 | 114 | 1055 |
| Shanbally | city | Donegal | Ireland | 55.16 | -7.98 | 1194 | 1296 |
| Shannagh | city | Donegal | Ireland | 54.59 | -8.05 | 341 | 1416 |
| Shannon | city | Donegal | Ireland | 54.84 | -7.56 | 183 | 4265 |
| Shellbrook | city | Donegal | Ireland | 55.02 | -7.58 | 0 | 1604 |
| Sheskinapoll | city | Donegal | Ireland | 54.91 | -7.57 | 830 | 2618 |
| Single Street | city | Donegal | Ireland | 54.48 | -8.26 | 3 | 3249 |
| Sir Albert's Bridge | city | Donegal | Ireland | 54.74 | -8.29 | 830 | 1275 |
| Sir Albert’s Bridge | city | Donegal | Ireland | 54.74 | -8.29 | 830 | 1275 |
| Slievebane | city | Donegal | Ireland | 55.37 | -7.34 | 68 | 598 |
| Sockar | city | Donegal | Ireland | 54.98 | -7.84 | 830 | 1404 |
| Soppog | city | Donegal | Ireland | 55.06 | -7.32 | 206 | 13247 |
| Speenoge | city | Donegal | Ireland | 55.04 | -7.43 | 249 | 3851 |
| Spíonóg | city | Donegal | Ireland | 55.04 | -7.43 | 249 | 3851 |
| Srath | city | Donegal | Ireland | 55.15 | -7.29 | 990 | 1301 |
| Srath Chaisil | city | Donegal | Ireland | 54.82 | -8.19 | 830 | 312 |
| Srath Laoill | city | Donegal | Ireland | 54.68 | -8.63 | 328 | 1269 |
| Srath Laoill Thuaidh | city | Donegal | Ireland | 54.69 | -8.64 | 839 | 1141 |
| Srath an Bhealaigh | city | Donegal | Ireland | 54.73 | -8.55 | 830 | 290 |
| Srath an Urlair | city | Donegal | Ireland | 54.80 | -7.77 | 193 | 4182 |
| Srath na Bruai | city | Donegal | Ireland | 55.09 | -8.27 | 249 | 1956 |
| Srath na gCartán | city | Donegal | Ireland | 54.73 | -8.61 | 830 | 417 |
| Srath na gCopóg | city | Donegal | Ireland | 55.17 | -7.24 | 830 | 1363 |
| St Johnston | city | Donegal | Ireland | 54.93 | -7.45 | 3 | 3624 |
| Straboy | city | Donegal | Ireland | 54.75 | -8.62 | 830 | 395 |
| Stracashel | city | Donegal | Ireland | 54.82 | -8.19 | 830 | 312 |
| Strahack | city | Donegal | Ireland | 55.08 | -7.49 | 29 | 2039 |
| Straid | city | Donegal | Ireland | 55.27 | -7.43 | 173 | 1795 |
| Straleel | city | Donegal | Ireland | 54.68 | -8.63 | 328 | 1269 |
| Straleel North | city | Donegal | Ireland | 54.69 | -8.64 | 839 | 1141 |
| Stralongford | city | Donegal | Ireland | 54.89 | -7.75 | 830 | 2456 |
| Stranabrooey | city | Donegal | Ireland | 55.09 | -8.27 | 249 | 1956 |
| Stranagappoge | city | Donegal | Ireland | 55.17 | -7.24 | 830 | 1363 |
| Stranagartan | city | Donegal | Ireland | 54.73 | -8.61 | 830 | 417 |
| Stranagoppoge | city | Donegal | Ireland | 55.17 | -7.24 | 830 | 1363 |
| Stranarva | city | Donegal | Ireland | 54.99 | -8.26 | 830 | 1690 |
| Stranorlar | city | Donegal | Ireland | 54.80 | -7.77 | 193 | 4182 |
| Straruddan | city | Donegal | Ireland | 55.25 | -7.15 | 82 | 1381 |
| Straths Bridge | city | Donegal | Ireland | 55.27 | -7.32 | 131 | 2217 |
| Stravally | city | Donegal | Ireland | 54.73 | -8.55 | 830 | 290 |
| Stream's Town | city | Donegal | Ireland | 55.13 | -7.72 | 32 | 1879 |
| Stream’s Town | city | Donegal | Ireland | 55.13 | -7.72 | 32 | 1879 |
| Stroove | city | Donegal | Ireland | 55.22 | -6.93 | 0 | 132 |
| Sui Corr | city | Donegal | Ireland | 54.94 | -7.90 | 259 | 644 |
| Swillybrin | city | Donegal | Ireland | 55.15 | -7.95 | 108 | 1388 |
| Súile Bruithne | city | Donegal | Ireland | 55.15 | -7.95 | 108 | 1388 |