| Conflict: | Battle of Cefn Digoll |
| Date: | c.630 |
| Place: | Long Mountain near Welshpool, Wales |
| Coordinates: | 52.65°N -7°W |
| Result: | Gwynedd-Mercian victory |
| Territory: | Northumbrian domination of Gwynedd ended |
| Combatant1: | Kingdom of Gwynedd Kingdom of Mercia |
| Combatant2: | Kingdom of Northumbria |
| Commander1: | Cadwallon ap Cadfan Penda of Mercia |
| Commander2: | Edwin of Northumbria |
| Strength1: | Unknown |
| Strength2: | Unknown |
| Casualties1: | Unknown |
| Casualties2: | Unknown |
The Battle of Cefn Digoll, also known as the Battle of the Long Mynd was fought in 630 at Long Mountain near Welshpool in modern-day Wales. The battle was fought between the Northumbrian army of King Edwin of Northumbria and an anti-Northumbrian alliance between King Cadwallon of Gwynedd and Penda of Mercia.[1] The battle ended the Northumbrian domination of Gwynedd, and preceded a Welsh campaign into Northumbria, which led to Edwin's death at the Battle of Hatfield Chase.