Brecknockshire
Historic counties data provided by Association of British Counties / Historic Counties Trust.
| Name | Location | County | Country | Power source | Type | Function | River |
| Defynnog Mill, Defynnog | Defynnog | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Senni |
| Esgair Moel Woollen Mill, Llanwrtyd | Llanwrtyd | Brecknockshire | United Kingdom | Water | Watermill | Woollen mill | Cledan |
| Felin Newydd, Llandetty | Llandetty | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | |
| Gileston Mill, Talybont-on-Usk | Talybont-on-Usk | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Caerfanell |
| Golden Grove Paper Mills, Llangenny | Llangenny, Vale of Grwyney | Brecknockshire | United Kingdom | Water | Watermill | Paper mill | Grwyne |
| Llangwathan Mill, Hay-on-Wye | Hay-on-Wye | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Dulas Brook |
| Melin y Cwm, Beulah | Beulah, Treflys | Brecknockshire | United Kingdom | Water | Watermill | Corn mill, Saw mill | Cnyffiad |
| Millbrook Mill, Llanhamlach | Llanhamlach | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Usk |
| Millbrook Paper Mill, Llangenny | Llangenny, Vale of Grwyney | Brecknockshire | United Kingdom | Water | Watermill | Paper mill | Grwyne |
| Nant-y-Garw Lead Mine, Llanwrthwl | Llanwrthwl | Brecknockshire | United Kingdom | Water | Watermill | Lead crushing mill, Mine mill/wheel | Nant-y-Garw |
| Pont-Faen Mill, Pont-Faen | Pont-Faen, Merthyr Cynog | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Ysgir |
| Priory Mill, Brecon | Brecon | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Honddu |
| Saw mill, Blaen Llynfi, Cathedine | Cathedine, Llanfihangel Cwmdu with Bwlch and Cathedine | Brecknockshire | United Kingdom | Water | Watermill | Saw mill | Llyfni |
| Talgarth Mill, Talgarth | Talgarth | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Ennig |
| Talybont Mill, Dyffryn | Dyffryn | Brecknockshire | United Kingdom | Water | Watermill | ||
| Upper Mill, Hay-on-Wye | Hay-on-Wye | Brecknockshire | United Kingdom | Water | Watermill | Corn mill, Paper mill | Dulas Brook |
| Usk Paper Mills, Glangrwyney | Glangrwyney, Vale of Grwyney | Brecknockshire | United Kingdom | Steam, Water | Watermill | Paper mill | Grwyne |
| Watermill, Hay-on-Wye | Hay-on-Wye | Brecknockshire | United Kingdom | Water | Watermill | Corn mill | Dulas Brook |
| Woollen mill, Brecon | Brecon | Brecknockshire | United Kingdom | Water | Watermill | Woollen mill | Honddu |