Cinco de Mayo is primarily a holiday in the state of Puebla, where Mexican militias under Gen. Zaragosa Seguin, defeated the French at the Battle of Puebla, 1862.
It temporarily stopped the French takeover, but additional troops were sent and the French installed Maxmilian as ruler. The French were expelled in 1867 and Maxmilian executed.

It has become an important celebration in several American cities with large Mexican immigrant populations, and along the border.

Commercial interests are often blamed for the spread of the holiday.