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ORDER OF BATTLE // June 18, 1813

Battle of San Millan-Osma

Estimated force strength by side, with confidence labels per surviving record.

Forces engaged

2 sides catalogued · combined 8,800–10,284 estimated

  • French Empire

    4,800

    Medium-confidence figure

  • United Kingdom

    4,000–5,484

    Medium-confidence figure

Battle context

The Battles of San Millán and Osma on 18 June 1813 formed part of Wellington's broader 1813 campaign in northeast Spain, a drive that brought two Allied divisions into sharp contact with two divisions of King Joseph Bonaparte's French army. The engagements proved costly to the French: the fight at San Millán was described as extremely punishing to Maucune's division, and a subsequent French attempt to hold a defensive position at Osma the same day was beaten back with little difficulty. Together the two actions degraded French cohesion at a critical moment in the campaign, stripping Joseph's army of the ability to anchor a line in the region and contributing to the unraveling of French operational control in northern Spain ahead of the decisive confrontation that followed.

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Sources (5)

Last verified June 2026
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