| Site name | Country | County | Nearest town | Site type | Access | Classification (girth in metres) | View on map |
|---|---|---|---|---|---|---|---|
| Ansford | England | Somerset | Castle Cary | churchyard | Yes | Notable | View On Map |
| Antrim Castle | Ireland | Co. Antrim | Antrim | historic site | Yes | Ancient 4m-5m | View On Map |
| Apethorpe Hall | England | Northamptonshire | Peterborough | planted avenue | Yes | Notable | View On Map |
| Apley Castle | England | Shropshire | Telford | parkland | Yes | Ancient 4m-5m | View On Map |
| Appin House Farm | Scotland | Argyll and Bute | Oban | estate | No | Notable | View On Map |
| Arangas | Spain | Asturias | Cangas de Onis | churchyard | Yes | Ancient 5m-7m | View On Map |
| Arborfield | England | Berkshire | Reading | former religious site | Yes | Ancient 4m-5m, Notable | View On Map |
| Ardingly – Brook House | England | Sussex - East | Haywards Heath | estate | No | Ancient 4m-5m | View On Map |
| Ardingly – churchyard | England | Sussex - West | Haywards Heath | churchyard | Yes | Ancient 7m+ | View On Map |
| Ardingly Stonehurst | England | Sussex - West | Haywards Heath | Ancient 5m-7m | View On Map | ||
| Ardsallagh House at Navan | Ireland | Co. Meath | Navan | former religious site | No | Ancient 5m-7m | View On Map |
| Ardtully Castle | Ireland | Co. Kerry | Kilgarvan | castle | Yes | Ancient 5m-7m | View On Map |
| Arganchy | France | Calvados - Normandie | Bayeux | churchyard | Yes | Ancient 4m-5m | View On Map |
| Arkengarthdale – Fell End | England | Yorkshire - North | Richmond | upland | Yes | Ancient 5m-7m | View On Map |
| Arlington | England | Devon | Barnstaple | churchyard | Yes | Ancient 4m-5m | View On Map |
| Armathwaite Hall | England | Cumbria | Cockermouth | parkland | Yes | Ancient 5m-7m | View On Map |
| Arndale Beck Sheepfold Scar – East | England | Yorkshire - North | Richmond | upland | Yes | Lost, Notable | View On Map |
| Arndale Beck Sheepfold Scar – West | England | Yorkshire - North | Richmond | upland | Yes | Ancient 4m-5m, Ancient 5m-7m, Lost | View On Map |
| Arndale Hole Lower Scar | England | Yorkshire - North | Richmond | upland | Yes | View On Map | |
| Arndale Springs – Upper Scar | England | Yorkshire - North | Richmond | upland | Yes | Ancient 4m-5m, Lost, Notable | View On Map |