墨西哥的獨立戰爭由1810年開始，一直到1821年解放軍纔進入墨西哥市，整個獨立戰爭由米格爾·伊達爾戈·伊·科斯蒂利亞發起，在1810年10月1日起義，推翻西班牙統治，但是9月起義計劃由於叛徒告密泄露，所以提早在9月16日的 Dolores 小鎮開始，成功後成立了第一共合國，瓜達盧佩維多利亞為其首任總統。
1810年墨西哥獨立戰爭領袖米格爾·伊達爾戈神父（Miguel Hidalgo）發動起義，反抗西班牙的殖民統治，標志墨西哥的獨立戰爭從此開始。1821年墨西哥取得獨立，翻開歷史新的一頁。
After Napoleon I invaded Spain in 1807 and put his brother, Joseph on the Spanish throne, Mexican Conservatives and rich land-owners who supported Spain's Bourbon royal family objected to the comparatively liberal Napoleonic policies. Thus an unlikely alliance was formed in Mexico: liberales, or Liberals, who favored a democratic Mexico, and conservadores, or Conservatives, who favored a Mexico ruled by a Bourbon monarch who would restore the status quo ante. These two elements agreed only that Mexico must achieve independence and determine her own destiny.
Taking advantage of the fact that Spain was severely handicapped under the occupation of Napoleon's army, Miguel Hidalgo y Costilla, a Catholic priest of Spanish descent and progressive ideas, declared Mexico's independence from Spain in the small town of Dolores at daybreak on 16 September 1810, with a proclamation now known as the "grito de Dolores". This act started the long war, the first official document of independence was the Solemn Act of the Declaration of Independence of Northern America signed in 1813 by the Congress of Anáhuac. Eventually led to the official recognition of independence from Spain in 1821 and the creation of the First Mexican Empire. As with many early leaders in the movement for Mexican independence, Hidalgo was captured by opposing forces and executed.
Miguel Hidalgo.
Prominent figures in Mexico's war for independence were Father José María Morelos, Vicente Guerrero, and General Agustín de Iturbide. The war for independence lasted eleven years until the troops of the liberating army entered Mexico City in 1821. Thus, although independence from Spain was first proclaimed in 1810, it was not achieved until 1821, by the Treaty of Córdoba, which was signed on August 24 in Córdoba, Veracruz, by the Spanish viceroy Juan de O'Donojú and Agustín de Iturbide, ratifying the Plan de Iguala.
In 1821, Agustín de Iturbide, a former Spanish general who switched sides to fight for Mexican independence, proclaimed himself emperor – officially as a temporary measure until a member of European royalty could be persuaded to become monarch of Mexico (see Mexican Empire for more information). A revolt against Iturbide in 1823 established the United Mexican States. In 1824, "Guadalupe Victoria" became the first president of the new country; his given name was actually Félix Fernández but he chose his new name for symbolic significance: Guadalupe to give thanks for the protection of Our Lady of Guadalupe, and Victoria, which means Victory.
After independence
After independence, several Spanish possessions in Central America which also proclaimed their independence were incorporated into Mexico from 1822 to 1823, with the exception of Chiapas and several other Central American states. The northern provinces grew increasingly isolated, economicaly and politically, due to prolonged Comanche raids and attacks. New Mexico in particular had been gravitating more toward Comancheria. In the 1820s, when the United States began to exert influence over the region, New Mexico had already begun to question its loyalty to Mexico City. By the time of the Mexican-American War large portions of northern Mexico had been systematically raided and pillaged by the Comanches, causing impoverishment, political fragmentation, and a general frustration with the inability, or unwillingness, of the Mexican government to curb the Comanches.
Soon after achieving its independence from Spain, the Mexican government, in an effort to populate some of its sparsely-settled northern land claims, awarded extensive land grants in a remote area of the state of Coahuila y Tejas to thousands of immigrant families from the United States, on the condition that the settlers convert to Catholicism and assume Mexican citizenship. It also forbade the importation of slaves, a condition that, like the others, was largely ignored. A key factor in the decision to allow American to settle Texas was the hope that the immigrants would help buffer and protect the province from Comanche attacks. It was also hoped that the policy would blunt American imperial expansion by turning the immigrants into Mexican citizens. The policy failed on both accounts, as the Americans tended to settle far from the Comanche raiding zones and used the failure of the central Mexican government to suppress the raids as a pretext for declaring independence.
First Republic
The government of the newly independent Mexico soon fell to rogue republican forces led by Antonio López de Santa Anna and others. The first Republic was formed with Guadalupe Victoria as its first president, followed in office by Vicente Guerrero who won the electoral vote but lost the popular vote. The Mexican constitution was at that time very similar to the US constitution; but was largely disregarded by the majority of the population. The conservative party saw the opportunity to control the government and led a revolution under the leadership of Gen. Anastasio Bustamante who became president from 1830 to early 1832. The federalists asked Gen. Antonio López de Santa Anna to overthrow Bustamante and he did, declaring General Manuel Gómez Pedraza (who won the electoral vote back in 1828) as the "true" president. Elections took place, and Santa Anna took office on 1832. Constantly changing political beliefs, as president (he was president eleven different times), in 1834 Santa Anna abrogated the federal constitution, causing insurgencies in the southeastern state of Yucatán and the northernmost portion of the northern state of Coahuila y Tejas. Both areas sought independence from the central government. After negotiations and the presence of Santa Anna's army eventually brought Yucatán to again recognize Mexican sovereignty, Santa Anna's army turned to the northern rebellion. The inhabitants of Tejas, calling themselves Texans and led mainly by relatively recently-arrived English-speaking settlers, declared independence from Mexico at Washington-on-the-Brazos, giving birth to the Republic of Texas. Texan militias defeated the Mexican army and captured General Santa Anna at the Battle of San Jacinto. Texas declared their independence from Mexico in 1836, further reducing the claimed territory of the fledgling Mexican republic. In 1845, Texans voted to be annexed by the United States, and this was agreed to by the U.S. Congress and signed into law by President John Tyler.