Tlalnepantla de Baz is one of 125 municipalities located in the state of Mexico, situated in the northeastern part of the region within the Valley of Mexico. It lies north of Mexico City and serves as a primary component of the dense Region XII, which it shares with Atizapán.
The city of Tlalnepantla serves as the municipal seat and is the largest city within the municipality. Its name originates from the Náhuatl words tlalli (land) and nepantla (middle), translating to "the middle land." Historically, the area was known as Tlalnepantla de Galeana and Tlalnepantla de Comonfort; the current designation of Baz honors Gustavo Baz Prada, a politician and soldier who served as Governor of the State of Mexico.
Geographically, the municipality includes an exclave to the west that is separated by the borough of Gustavo A. Madero. The region is characterized by its high population density and its proximity to the capital city.