Answer:
In the United States, Cinco de Mayo, or May 5, is seen as the day to celebrate Mexican food, culture, and traditions. Of course, it's also a great excuse to enjoy some Mexican drinks. Many who celebrate in the U.S. assume—incorrectly—that Cinco de Mayo is Mexico's Independence Day.
In contrast, Cinco de Mayo in Mexico is celebrated in a very low-key manner. Students get the day off, but banks and government offices are open. The only major parades and fiestas taking place south of the border are held in the city of Puebla, where there's a military parade and a mock battle is staged to commemorate the Battle of Puebla, the event that gave rise to the holiday.
So why is Cinco de Mayo celebrated with such fanfare in the United States? As with many holidays, a lot of the celebration is due to marketing. People across the U.S., whether of Mexican heritage or not, use the day as an excuse to eat Tex-Mex cuisine, drink Mexican beers, and prepare pitchers of margaritas, and the holiday is often associated with partying.
However, just as Saint Patrick's Day is a day to celebrate Irish culture for Irish-Americans, Cinco de Mayo has become a day for Mexican-Americans to show pride in their own unique culture. Since it's not widely celebrated in Mexico, the holiday can be seen more as a Mexican-American holiday than a Mexican one.
