The Battle of Sahagún (21 December 1808) was a cavalry clash at Sahagún, Spain, in which the British 15th Light Dragoons (Hussars) defeated two regiments of French cavalry during the Corunna Campaign of the Peninsular War. Losses to one of the French regiments were so heavy that it was subsequently disbanded. The action marked the final phase of the British army's advance into the interior of Spain, before they began their harrowing retreat to the coast and ultimate evacuation by sea.