Chimalhuacán (Nahuatl for "place of those who have shields") is a city and municipality located in the eastern part of Mexico State, Mexico. It lies just outside the northeast border of the Federal District (Distrito Federal) and is part of the Greater Mexico City urban area.
Chimalhuacán was founded 1259 by three chiefs or tlatoani named Huauxomatl, Chalchiutlatonac and Tlatzcantecuhtli. These chiefs and their people originated from Tula and Culhuacán. They spoke Chichimeca y Mexicalanguages but with time their customs merged and Náhuatl became the dominant language. It became subject to Texcoco, and through that belonged to the Aztec Triple Alliance in 1431. The Spanish town of Chimalhuacán was founded in 1529 and the Dominicans built a church and monastary here in 1563.
The municipality has an area of 46.61 km² (17.996 sq mi). The adjacent municipalities are Ciudad Nezahualcóyotl, Atenco, Texcoco, Chicoloapan, and La Paz. The city is the fifth largest in the state in population (after Ecatepec de Morelos, Ciudad Nezahualcóyotl, Naucalpan de Juárez, and Tlalnepantla de Baz).