Cinco de Mayo is most celebrated in the United States, particularly in cities with large Mexican-American populations. Notable celebrations occur in Los Angeles, California, which hosts Fiesta Broadway, the largest Cinco de Mayo event in the world, featuring parades, mariachi music, traditional Mexican food, and carnival rides

. Other major U.S. cities with significant festivities include San Antonio, Texas, Denver, Colorado, and Washington, D.C.

. In Mexico, Cinco de Mayo is primarily celebrated in the state of Puebla, where the historic Battle of Puebla took place in 1862. The celebrations there are more ceremonial, including military parades, speeches, and reenactments of the battle

. Outside Puebla, Cinco de Mayo is not widely observed across Mexico and is considered a minor holiday compared to Mexican Independence Day on September 16

. In summary:

• United States: Largest and most widespread celebrations, especially in Los Angeles, San Antonio, Denver, and other cities with Mexican-American communities. The holiday has become a cultural celebration of Mexican heritage with parades, music, food, and festivals

• Mexico: Mainly celebrated in Puebla with traditional ceremonies and reenactments; less prominent elsewhere in the country

Thus, Cinco de Mayo is most famously and extensively celebrated in the U.S., while in Mexico it remains a regional and more historically focused observance.