Ol San Antone will celebrate it tonight on the river. Amazing more people in San Antone do not get the connection that April 21 and Fiesta "happen" to occur each year at the same time. Battle of Flower's etc.
Cinco de Mayo is not a big deal in most of Mexico either beyond the state where the battle took place (Puebla). This day has been elevated by beer companies mostly in the US. Diez y Seis de Septiembre is Mexican Independence Day (from Spain). This is a big deal and a holiday in Mexico.
re Cinco de Mayo in Puebla: went to Puebla and rented a taxi for the day to go to Cholula to photograph some of the hundred or so churches there. At the end of day I returned to Puebla and asked my driver to show me the battle site and the memorial to General Zaragoza, who was born in Goliad Texas just down the road from my hometown. He showed me and told me General Zaragoza was a close friend and ally of Pancho Villa (their deaths were about 55 years apart and they did not know each other); I told him he was mistaken and he insisted they were buddies. Most Mexicans, like most Americans, don't know squat about their own history.
The site for the last St. Patrick's festival in Ireland said that it had 1.1 million attendees. The population of the Rep. of Ireland is only 4.6 million. So... you could say it's kind of a big deal.