To the north, Coahuila accounts for a 512 kilometers (318 mi) stretch of the U.S. - Mexico border, adjacent to the U.S. state of Texas along the course of the Rio Grande (Río Bravo del Norte). Coahuila also borders the Mexican states of Nuevo León to the east, Zacatecas and San Luis Potosi to the south, and Durango and Chihuahua to the west. With an area of 151,571 square kilometers (58,521.9 sq mi), it is the nation's third-largest state. It comprises 38 municipalities (municipios). In 2005, Coahuila's population was 2,495,200 inhabitants.
Coahuila's population is comprised mainly of people of European ancestry, making up 74 percent of the population. The second-largest ethnic group is the Mestizo (European-Amerindian) who are 20 percent of the population, and the smallest ethnic group is the Amerindian, comprising 1 percent of Coahuila's population. The rest of the population is composed of American, Canadian, and Japanese communities.
The capital of Coahuila and its largest city is Saltillo. Coahuila also includes the cities of Torreón (the largest metropolitan area of the state but part of this metro area is in the neighboring state of Durango), Monclova (a former state capital), Piedras Negras, and Ciudad Acuña.