The borders of the viceroyalty, which had arrived in the century. XVI up to the north of Panamá, and which for a time had also included, under the dependence of the viceroy, Venezuela, the Antilles, the Philippines (from 1565 to 1584), came to embrace Louisiana following the Treaty of Paris of 1783. After the unfortunate campaigns of the governor of Louisiana, Bernardo de Gálvez, later viceroy of Mexico (1785-1786), the borders reached as far as Florida, which was also, although only in name, dependent on the viceroyalty. Having returned Louisiana to France in 1802 and decreed the annexation of Florida to the United States in 1812, after it had expressed its will to do so, the northern frontier of New Spain was extended in 1821 from Louisiana to Oregon. First, the energetic Giovanni Battista Anna,commandancia constituted for the three distant provinces of N., and to centralize it instead in relations with Spain. All this in correlation with the ordinances of 1786, drawn up according to the project of Giuseppe de Gálvez, visitor to New Spain from 1765 to 1771. But the new organization, aimed above all at avoiding serious abuses by the minor authorities and at making financial administration more effective and the exploitation of the colony for the benefit of Spain, added bait to the discontent of the residents of Mexico: and all the more so since an ordinance provided that there was “in every country of the Indians, which belonged to some of the districts into which the provinces are divided”, a “necessarily Spanish” sub-delegate. This arrangement displeased the Creoles and the rest of the Mexican population,

In the complex organism of New Spain, as in the other Spanish dominions, the only force that held everyone together was the king, in whom public life was embodied, and especially in the eyes of the Indians and also of the Spaniards and Creoles, but not of the mestizos, he represented a kind of last refuge and defense, a kind of last terrestrial resort. There was a general persuasion that if the colony authorities committed unjust acts, they could be removed from their posts; and they were generally removed after a certain time by the will of the king, who was capable of annihilating the strongest forces, as he had done, at least in appearance, with the Jesuits. And this persuasion, which was the basis of the life of the colony, led to absolutism, which found its highest expression under the regime of the stewards.

So when, suddenly, Spain was left without a king, since those who could be so by law had fallen into the power of Napoleon, the only element of cohesion between the classes and the mother country disappeared: then the colonies began the struggle for independence., which was a real civil war and was to lead to their detachment from the metropolis. On September 12, 1808, Francesco Primo Verdad y Ramos, mayor of the municipal council of Mexico, declared that, once the monarchs disappeared, the sovereign power of the countries should be assumed by the municipal councils, these being the organs of government that most directly represent the people, and the people being “immortal”. This first effort towards independence, which found weak support from the viceroy Giuseppe de Iturrigaray, was in vain, later removed by the Spaniards who were at the head of the colony, the proclamation of autonomy was made by the parish priest Michele Hidalgo y Castilla, no longer for the casual reason of the disappearance of the kings, but for the ancient and peremptory reason of the inequality in which the population of colony was held and everyone’s aspiration to freedom. The war broke out on September 16, 1810. Ten and a half months later Michele was shot; and, after 5 years and 5 months, his great successor, the mongrel priest Giuseppe Maria Morelos, soul of the first republican organization effort in Mexico, was also shot. The independents remained almost defeated: until, on March 9, 1820, the constitution of 1812 by Ferdinand VII was sworn and a resolute policy against the clergy began in Spain, Agostino de Itúrbide proclaimed with Plan de Iguala, February 24, 1821, the independence, the preservation of the Catholic Church, against the dominance of which violent measures were already being developed in the metropolis, and the union of all the residents of the country. Both the survivors of the initial movement, headed by Vicente Guerrero, as well as those who had already been his opponents, and the Spaniards themselves, cooperated in this policy. The Plan de Iguala was accepted by Giovanni O ‘Donojú, the last viceroy of Mexico, who signed with Itúrbide, on August 24 of that year,  the treaties of Córdoba, the triumphal entry into Mexico of the liberating army, on the 27th September 1821, sealed the conquered independence.

According to Sourcemakeup, the area of ​​New Spain was then more than 4,000,000 sq km. The population, calculated (1810) by Navarro Noriega at 6,122,454 residents, included about 70,000 Spaniards, about one million Creoles, 3,700,000 Indians and one and a half million mestizos.

The economic and political inequality of the country in relation to Spain and that of almost all the residents in relation to the Spaniards who were in Mexico, had constituted the essential flaw of the regime during the viceroyalty. The unification of the country and the formation of the individual and collective consciousness of it, as a whole connected with the civil world, by virtue of the Spanish language, the Christian religion and the ability to govern itself, are the lasting result of the Spanish conquest and the cooperation of the constituent elements of New Spain, and explain its further history with the survival of various ancient antagonisms.