The Battle of Celaya on the 13th of April 1915 was the single bloodiest battle of the Mexican Revolution. The Constitutionalist forces under Pancho Villa were badly defeated by forces under the command of Álvaro Obregón, who supported the presidency of Venustiano Carranza. Villa lost around 4,000 men killed in frontal attacks.

In this battle, Obregón developed a wise defense "in depth" that proved very effective against the cavalry charges and artillery techniques used at that time. This battle was a turning point in the future of Villa, the Revolution and Mexican history in the XXth century.