| Site name | Country | County | Nearest town | Site type | Access | Classification (girth in metres) | View on map |
|---|---|---|---|---|---|---|---|
| Maentwrog | Wales | Gwynedd | Porthmadog | churchyard | Yes | Ancient 5m-7m, Lost | View On Map |
| Maesmynis | Wales | Powys | Builth Wells | churchyard | Yes | Ancient 4m-5m | View On Map |
| Maesyrychen Mountain | Wales | Denbighshire | Bala | field | No | Notable | View On Map |
| Magny – en – Bessin | France | Calvados - Normandie | Bayeux | churchyard | Yes | Ancient 4m-5m | View On Map |
| Maiden Bradley | England | Wiltshire | Frome | churchyard | Yes | Notable | View On Map |
| Maizet | France | Calvados - Normandie | Caen | churchyard | Yes | Notable | View On Map |
| Malleny Gardens – Balerno | Scotland | City of Edinburgh | Edinburgh | garden | Yes | Notable | View On Map |
| Mallwyd | Wales | Gwynedd | Dolgellau | churchyard | Yes | Ancient 5m-7m, Ancient 7m+, Lost | View On Map |
| Mamhead | England | Devon | Exeter | churchyard | Yes | Ancient 7m+ | View On Map |
| Mamhilad | Wales | Monmouthshire | Pontypool | churchyard | Yes | Ancient 5m-7m, Ancient 7m+, LostNotable | View On Map |
| Manafon | Wales | Powys | Welshpool | churchyard | Yes | Ancient 5m-7m, Ancient 7m+ | View On Map |
| Manaton | England | Devon | Moretonhampstead | churchyard | Yes | Ancient 5m-7m | View On Map |
| Mandeville | France | Eure - Normandie | Rouen | churchyard | Yes | Ancient 5m-7m | View On Map |
| Manest Court | Wales | Powys | Brecon | former religious site | No | Lost | View On Map |
| Mansel Lacy | England | Herefordshire | Hereford | churchyard | Yes | Ancient 4m-5m | View On Map |
| Manston | England | Dorset | Sturminster Newton | churchyard | Yes | Lost | View On Map |
| Maplebeck | England | Nottinghamshire | Newark-on-Trent | churchyard | Yes | Ancient 5m-7m | View On Map |
| Mappowder | England | Dorset | Sturminster Newton | churchyard | Yes | Ancient 4m-5m, Notable | View On Map |
| Marbury | England | Cheshire | Whitchurch | churchyard | Yes | Lost | View On Map |
| Marchwood – Warwicks Copse | England | Hampshire | Southampton | woodland | Yes | Ancient 4m-5m | View On Map |