ANAHUAC, a geographical district of Mexico, limited by the traditional and vaguely defined boundaries of an ancient Indian empire or confederation of that name previous to the Spanish _ conquest. The word signifies "country by the waters" in the old Aztec language ; hence the theory that Anahuac was located on the sea coast. Anahuac has been described as all the plateau region of Mexico, with an area equal to three-fourths of the republic, and extending between the eastern and western coast ranges from Rio Grande to the Isthmus of Tehuantepec. But it properly is the great plateau valley in which the city of Mexico is located, between 18° 4o' and 2o° 3o' N. lat., about aoom. long by 75m. wide, with an average elevations of 7.5ooft., and a mean temperature of 62°. The existence of the name in southern Utah, United States, and on the Gulf coast of Mexico, has given rise to theories of other locations and wider bounds for the old Indian empire.