Really the holiday is on the 20th of November and is known as Revolution day. The 19th is a "Puente" or bridge in English meaning that they decided to take Monday off so as to give many people a 3 day weekend. Most celebrations and parades will be on the 20th November and the actual history of this special day is in the following article:
November 20th Holiday in Mexico 
The 20th of November is celebrated in Mexico as the declaration of a Mexican revolution that began on this day in 1910 due to a plan issued by a writer and revolutionist Francisco Ignacio Madero. So this was the beginning of a revolution and the not the end as many seem to think. In fact it is commonly called Revolution Day here in Mexico and it did not have anything to do with the Spanish or French occupations that had been in the past.
On November 20th of 1910 Francisco Ignacio Madero started this Mexican revolution against the ruling President of Mexico at the time, Jose de la Cruz Porfirio Diaz Mori. On the 20th of November was a call to arms in a document called the Plan of San Luis Potosi written by Madero in San Antonio Texas and published in San Luis Potosi Mexico. The plan was a call to all Mexicans to raise arms against and to bring down the authoritarian dictatorship of President Porfirio Diaz.
Franciso Ignacio Madero
Earlier in the year of 1910 during the elections that President Diaz claimed were to be to fair and return democracy to Mexico, however Diaz jailed Madero and approximately 6000 of his Maderista, anti-reelectionist compadres. Not allowing Madero to participate in the elections after he and his wife had vigorously campaigned against Diaz and Madero had become known as the “Apostle of Democracy”. After Diaz was elected President; Madero was then allowed some freedoms like to ride around San Luis Potosí during the day under armed guard. He then was able to flee Mexico to San Antonio, Texas via the Mexican U.S border at Laredo on October 4th 1910.
The Plan of San Luis Potosí asked for the nullification of the elections of 1910 and to physically take up arms against the Mexican government. Madero explained the necessity of these actions due to the extremity of the situation and the lack of independance that the Mexican people were living in.
Here is the beginning of the Plan of San Luis Potosí translated into English
” Peoples, in their constant efforts for the triumph of the ideal of liberty and justice, are forced, at precise historical moments, to make their greatest sacrifices.
Our beloved country has reached one of those moments. A force of tyranny which we Mexicans were not accustomed to suffer after we won our independence oppresses us in such a manner that it has become intolerable. In exchange for that tyranny we are offered peace, but peace full of shame for the Mexican nation, because its basis is not law, but force; because its object is not the aggrandizement and prosperity of the country, but to enrich a small group who, abusing their influence, have converted the public charges into fountains of exclusively personal benefit, unscrupulously exploiting the manner of lucrative concessions and contracts.”
This document did begin the revolution and eventually in 1911 Madero was declared President of Mexico. While he was not President for long being assassinated in 1913 the revolution he started actually lasted through many years and many battles that included such famous revolutionists as Zapata and Pancho Villa with its official termination in 1924 with the election of President Plutarco Elias Calles succeeding President Alvaro Obregon.
Viva la Revolución! Viva Mexico!
