Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza (Spanish: Estado Libre y Soberano de Coahuila de Zaragoza), is one of the thirty-one states which, along with Mexico City, compose the thirty-two Federal Entities of Mexico.

Coahuila borders the Mexican states of Nuevo León to the east, Zacatecas and San Luis Potosí to the south, and Durango and Chihuahua to the west.

To the north, Coahuila accounts for a 512 kilometer- (three hundred and eighteen mile-) stretch of the Mexico–United States border, adjacent to the U.S. state of Texas along the course of the Rio Grande (Río Bravo del Norte).

With an area of 151,563 square kilometers (58,519 sq mi), it is the nation's third-largest state.

It comprises thirty-eight municipalities (municipios).

In 2010, Coahuila's population is 2,748,391 inhabitants.

The five largest cities in Coahuila are the state capital city of Saltillo; the second largest is Torreón (largest metropolitan area in Coahuila and 9th largest in Mexico), third largest is Monclova (a former state capital), fourth largest is Ciudad Acuña, and fifth largest is Piedras Negras.