The seven caves of Chicomoztoc, from Historia Tolteca-Chichimeca
Aztlán (from Nahuatl languages: Aztlān, Nahuatl pronunciation: [ˈast͡ɬaːn](listen)) is the ancestral home of the Aztec peoples. Aztecah is the Nahuatl word for "people from Aztlan". Aztlan is mentioned in several ethnohistorical sources dating from the colonial period, and each of them give different lists of the different tribal groups who participated in the migration from Aztlan to central Mexico, but the Mexica who went on to found Mexico-Tenochtitlan are mentioned in all of the accounts. Historians have speculated about the possible location of Aztlan and tend to place it either in northwestern Mexico or the southwest US, although there are doubts about whether the place is purely mythical or represents a historical reality.
Nahuatl legends relate that seven tribes lived in Chicomoztoc, or "the place of the seven caves". Each cave represented a different Nahua group: the Xochimilca, Tlahuica, Acolhua, Tlaxcalteca, Tepaneca, Chalca, and Aztec. Because of their common linguistic origin, those groups are called collectively "Nahuatlaca" (Nahua people). These tribes subsequently left the caves and settled "near" Aztlán.
The various descriptions of Aztlán apparently contradict each other. While some legends describe Aztlán as a paradise, the Codex Aubin says that the Aztecs were subject to a tyrannical elite called the Azteca Chicomoztoca. Guided by their priest, the Aztec fled, and, on the road, their god Huitzilopochtli forbade them to call themselves Azteca, telling them that they should be known as Mexica. Scholars of the 19th century—in particular Alexander von Humboldt and William H. Prescott—translated the word Azteca, as is shown in the Aubin Codex to Aztec.
Some say that the southward migration began on May 24, 1064 CE, after the Crab Nebula events from May to July 1054. Each of the seven groups is credited with founding a different major city-state in Central Mexico.
A 2004 translation of the Anales de Tlatelolco gives the only date known related to the exit from Aztlan; day-sign "4 Cuauhtli" (Four Eagle) of the year "1 Tecpatl" (Knife) or 1064–1065, and correlated to January 4, 1065.
Cristobal del Castillo mentions in his book "Fragmentos de la Obra General Sobre Historia de los Mexicanos", that the lake around the Aztlan island was called Metztliapan or "Lake of the moon." 
While Aztlán has many trappings of myth, similar to Tamoanchan, Chicomoztoc, Tollan, and Cibola, archaeologists have nonetheless attempted to identify a geographic place of origin for the Mexica.
Friar Diego Durán (c. 1537–1588), who chronicled the history of the Aztecs, wrote of Aztec emperor Moctezuma I's attempt to recover the history of the Mexica by congregating warriors and wise men on an expedition to locate Aztlán. According to Durán, the expedition was successful in finding a place that offered characteristics unique to Aztlán. However, his accounts were written shortly after the conquest of Tenochtitlan and before an accurate mapping of the American continent was made; therefore, he was unable to provide a precise location.
The meaning of the name Aztlan is uncertain. One suggested meaning is "place of Herons" or "place of egrets"—the explanation given in the Crónica Mexicáyotl—but this is not possible under Nahuatl morphology: "place of egrets" is Aztatlan. Other proposed derivations include "place of whiteness" and "at the place in the vicinity of tools", sharing the āz- element of words such as teponāztli, "drum" (from tepontli, "log").
The concept of Aztlán as the place of origin of the pre-Columbian Mexican civilization has become a symbol for various Mexican nationalist and indigenous movements.
In 1969 the notion of Aztlan was introduced by the poet Alurista (Aberto Baltazar Urista Heredia) at the National Chicano Youth Liberation Conference held in Denver, Colorado by the Crusade for Justice. There he read a poem, which has come to be known as the preamble to El Plan de Aztlan or as "El Plan Espiritual de Aztlan" due to its poetic aesthetic. For Chicanas/os, Aztlan refers to the Mexican territories annexed by the United States as a result of the Mexican–American War of 1846–1848. Aztlán became a symbol for mestizo activists who believe they have a legal and primordial right to the land. In order to exercise this right, some members of the Chicano movement propose that a new nation be created, a República del Norte.
Marx-Engels-Lenin Institute (U.S.), which demands self-determination for indigenous nations of all countries, as well as the immediate granting of self-determination of internally colonized nations of the US, up to and including secession.
Hunter S. Thompson in his article "Strange Rumblings In Aztlan", about the killing of Los Angeles journalist Ruben Salazar by the Los Angeles Police Department, Rolling Stone magazine, #81, April 29, 1971.
Aztlàn becomes independent in Harold Convington’s Northwest independence novels in which the nation of Aztlán becomes independent after President Chelsea Clinton agrees to let the Northwest American Republic secede.
Mexican-American extreme metal band Brujeria recorded the song "California Uber Aztlán", a cover version of the Dead Kennedys song "California Über Alles" with Spanish lyrics. While "California Über Alles" criticized Governor of California Jerry Brown, "California Uber Aztlán" talks about Governor of California Pete Wilson (referred to as "Pito Wilson") and the Chicano Movement.
The Mexican band Zoé published in 2018 an album titled "Aztlán" with a song by the same name. It mentions what was the city of Aztlán and even Tenochtitlán.
Andrews, J. Richard (2003). Introduction to Classical Nahuatl (revised ed.). Norman: University of Oklahoma Press. ISBN0-8061-3452-6. OCLC50090230.
Clavigero, Francesco Saverio (1807) . The history of Mexico. Collected from Spanish and Mexican historians, from manuscripts, and ancient paintings of the Indians. Illustrated by charts, and other copper plates. To which are added, critical dissertations on the land, the animals, and inhabitants of Mexico, 2 vols. Translated from the original Italian, by Charles Cullen, Esq. (2nd ed.). London: J. Johnson. OCLC54014738.
Vollemaere, Antoon Leon (2000). "Chimalma, first lady of the Aztecan migration in 1064"(PDF). Gender and Archaeology Across the Millennia: Long Vistas and Multiple Viewpoints. Sixth Gender and Archaeology Conference, October 6–7, 2000 (online collection of papers presented ed.). Flagstaff: Northern Arizona University, Department of Anthropology and Women's Studies. Archived from the original(PDF online publication) on 2008-04-14. Retrieved 2007-12-28.