Original: Cinco de Mayo ( Spanish for '' fifth of May '' ) is a holiday held on May 5 that commemorates the Mexican army 's unlikely victory over French forces at the Battle of Puebla on May 5 , 1862 , under the leadership of General Ignacio Zaragoza SeguÃ n/O. It is celebrated primarily in the state of Puebla and in the United States .
Simplified: In the Mexican state of Puebla , Cinco de Mayo is celebrated because the Mexican army won the Battle of Puebla from the French army on May 5 , 1862 .