Anahuac, an aboriginal name, signifying, in the Nahuatl or ancient Mexican language, by or near the water; from att, water, and nahuac, near. The name has come to be applied specifically to the valley, or rather the plateau of the city of Mexico, although in the early writers we find references to several Anahuacs; as, for instance, Anahuac-Ayotlan and Anahuac-Xicalanco, the latter applied to the district around the lake or lagoon of Xicalanco in Tabasco. From the circumstance of their having established themselves originally around the lakes of Chalco and Tezcuco, the traditional tribes of Mexico have been called Ana-hualtecas, people living by the water. It is alleged that these tribes came from some northern region, supposed by some to have been from Asia by way of Behring strait, and that the ruins of ancient edifices, known as casas grandes, in New Mexico and Chihuahua, mark the path of their migration. It is, however, known to critical students that their original seats, figuratively represented as seven caves, were somewhere in the vicinity, probably on some of the islands, of Lake Michoacan; and that when they reached the region of Anahuac, they were simple barbarians, clothed in skins and living by the chase.

Around the lakes of Mexico, however, they found the feeble remnants of a people far advanced in civilization, agriculturists and architects - the Tulhuatecas, a name corrupted by uncritical writers into Toltecs. These Tulhuateeas were unable to resist the irruption of the seven warlike tribes, but gradually taught them agriculture and the arts, and thus laid the foundation of the Tezcucan and Mexican empires, in which civilization and barbarism, lofty religious precepts and the most cruel rites, were incongruously mingled. The Anahualtecas were precisely the people better known as Aztecs (see Aztecs); and the name of Anahuac is now only understood as applying to the plateau of the city of Mexico. - This great table land comprises three fifths of the territory belonging to the Mexican republic, and has an elevation of 4,000 to 8,000 feet above the level of the sea. E. and W. it is bounded by the two great chains of mountains into which the Cordillera of Central America is subdivided in its northward progress.

Out of this plateau rise many lofty mountains, including the stupendous volcanoes of Jorullo and Popocatepetl, but it is generally level.