Archaeological, historical and linguistic evidence suggest that the Nahuas originally came from the deserts of northern Mexico (Aridoamerica) and migrated into central Mexico in several waves.
The presence of the Mexicanero people (who speak a Nahuatl dialect) in this area until the present day affirms this theory.

Before the Nahuas entered Mesoamerica, they were probably living for a while in northwestern Mexico alongside the Cora and Huichol peoples.
The first group of Nahuas to split from the main group were the Pochutec who went on to settle on the Pacific coast of Oaxaca possibly as early as 400 BCE.
From c. 600 BCE the Nahua quickly rose to power in central Mexico and expanded into areas earlier occupied by Oto-Manguean, Totonacan and Huastec peoples.
Through their integration in Mesoamerican the Mesoamerican cultural area the Nahuas adopted many cultural traits including maize agriculture and urbanism, religious practices including a ritual calendar of 260 days and the practice of human sacrifices and the construction of monumental architecture and the use of logographic writing.

Around 1000 CE the Toltec people, normally assumed to have been of Nahua ethnicity, established dominion over much of central Mexico which they ruled from Tollan Xicocotitlan.

From this period on the Nahua were the dominant ethnic group in the Valley of Mexico and far beyond, and migrations kept coming in from the north.
After the fall of the Toltecs a period of large population movements followed and some Nahua groups such as the Pipil and Nicarao arrived as far south as Nicaragua.
And in central Mexico different Nahua groups based in their different "Altepetl" city-states fought for political dominance.
The Xochimilca, based in Xochimilco ruled an area south of Lake Texcoco; the Tepanecs ruled the area to the west and the Acolhua ruled an area to the east of the valley.
One of the last of the Nahua migrations to arrive in the valley settled on an island in the Lake Texcoco and proceeded to subjugate the surrounding tribes.
This group were the Mexica who during the next 300 years became the dominant ethnic group of Mesoamerica ruling from Tenochtitlan their island capital.
They formed the Aztec Empire after allying with the Tepanecs and Acolhua people of Texcoco, spreading the political and linguistic influence of the Nahuas well into Central America.
Archaeological, historical and linguistic evidence suggest that the Nahuas originally came from the deserts of northern Mexico (Aridoamerica) and migrated into central Mexico in several waves. The presence of the Mexicanero people (who speak a Nahuatl dialect) in this area until the present day affirms this theory. 
Before the Nahuas entered Mesoamerica, they were probably living for a while in northwestern Mexico alongside the Cora and Huichol peoples. The first group of Nahuas to split from the main group were the Pochutec who went on to settle on the Pacific coast of Oaxaca possibly as early as 400 BCE. From c. 600 BCE the Nahua quickly rose to power in central Mexico and expanded into areas earlier occupied by Oto-Manguean, Totonacan and Huastec peoples. Through their integration in Mesoamerican the Mesoamerican cultural area the Nahuas adopted many cultural traits including maize agriculture and urbanism, religious practices including a ritual calendar of 260 days and the practice of human sacrifices and the construction of monumental architecture and the use of logographic writing.
Around 1000 CE the Toltec people, normally assumed to have been of Nahua ethnicity, established dominion over much of central Mexico which they ruled from Tollan Xicocotitlan.
From this period on the Nahua were the dominant ethnic group in the Valley of Mexico and far beyond, and migrations kept coming in from the north. After the fall of the Toltecs a period of large population movements followed and some Nahua groups such as the Pipil and Nicarao arrived as far south as Nicaragua. And in central Mexico different Nahua groups based in their different "Altepetl" city-states fought for political dominance. The Xochimilca, based in Xochimilco ruled an area south of Lake Texcoco; the Tepanecs ruled the area to the west and the Acolhua ruled an area to the east of the valley. One of the last of the Nahua migrations to arrive in the valley settled on an island in the Lake Texcoco and proceeded to subjugate the surrounding tribes. This group were the Mexica who during the next 300 years became the dominant ethnic group of Mesoamerica ruling from Tenochtitlan their island capital. They formed the Aztec Empire after allying with the Tepanecs and Acolhua people of Texcoco, spreading the political and linguistic influence of the Nahuas well into Central America.
Nahuas