| Site name | Country | County | Nearest town | Site type | Access | Classification (girth in metres) | 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 |
| Mardale | England | Cumbria | Shap | former religious site | No | Lost | View On Map |
| Marden | England | Herefordshire | Hereford | churchyard | Yes | Lost | View On Map |
| Mariners Hill – nr Westerham | England | Kent | Sevenoaks | field | Yes | Ancient 4m-5m | View On Map |
| Mark | England | Somerset | Bridgwater | churchyard | Yes | Lost | View On Map |
| Market Bosworth – Bosworth Hall | England | Leicestershire | Leicester | garden | Yes | Ancient 4m-5m | View On Map |
| Market Harborough | England | Leicestershire | Leicester | garden | Yes | Ancient 4m-5m | View On Map |
| Markwells Wood | England | Hampshire | Horndean | woodland | No | Ancient 5m-7m | View On Map |
| Marlay Park – Rathfarnham | Ireland | Dublin | Dublin | estate | Yes | Ancient 5m-7m | View On Map |
| Marldon | England | Devon | Torquay | churchyard | Yes | Notable | View On Map |
| Marston Bigot | England | Somerset | Frome | former religious site | No | Ancient 7m+ | View On Map |
| Marston Montgomery | England | Derbyshire | Uttoxeter | churchyard | Yes | Notable | View On Map |
| Marston St.Lawrence | England | Northamptonshire | Banbury | churchyard | Yes | Ancient 5m-7m | View On Map |