I'm Mexican, and our independence day is September 16, 1810. But when the Mexicans striked "treson" to Spain was the 15th. In Mexico we call it "El Grito De Dolores." Mexico wasn't the only country that got it's independence that day. El Salvador also got it's indipendence from Spain the same day. And a lot of hispanic countries did too, thats why Hispanic Heritage Month starts on September 15th, because of their independence day.