It is the main centre of population in the Leonese part of the Tierra de Campos natural region.

The Battle of Sahagún was a notable victory by the British light cavalry against their more numerous French adversaries in 1808.

The first settlement on the site grew up around the nearby Benedictine monastery consecrated to the saints Facundus and Primitivus.

On 25 November 1085, this latter king promulgated the edicts known as the Fuero de Sahagún, which gave a number of privileges to the Monastery and town, fomenting its growth.

Friction often erupted into disputes between the townsfolk and the monastery in the mid-12th century, as recorded in the Crónicas anónimas de Sahagún.