Tlahualilo is one of the 39 municipalities in which the state of Durango is divided. It is located in the northeast corner of the same and adjoins to the north with the municipalities of Jiménez, Chihuahua and Sierra Mojada, Coahuila, to the south with Gómez Palacio, Durango, to the east with Francisco I. Madero, Coahuila, and to the west with the municipality of Mapimí, Durango. Its geographical coordinates are 26°06'23'' north latitude and 103°26'34'' west longitude, it has an altitude of 1,095 meters above sea level, with a territorial extension of 3,709.8 km. Squares. The current population is 22,895 inhabitants, representing 1.30% of the total in the state.
In terms of population density, there are 4.8 inhabitants per square kilometer, with the main communities being: Tlahualilo de Zaragoza, El Lucero, San Francisco de Horizonte, Jauja, Banco Nacional and San Julio.