COAHUILA, a northern frontier State of Mexico, bounded N. and N.E. by Texas, U.S.A., E. by Nuevo Leon, S. by San Luis Potosi and Zacatecas, and W. by Durango and Chihuahua. Area, 58,067 sq.m. The population in 1930 was 433,00o. Its surface is a roughly broken plateau, traversed by several ranges of mountains and sloping gently toward the Rio Grande. In the western part there exist extensive areas of level land, many of them enclosed drainage basins, the largest of which is the Bolson de Mapimi, a great depression which was long considered barren and uninhabitable. Experiments with irrigation, however, have been highly successful and considerable tracts have since been brought under cultivation. In general the State is insufficiently watered, the rainfall being light and the rivers small. The rivers flow eastward to the Rio Grande. The climate is hot and dry, and generally healthy. Stock-raising was for a time the principal industry, but agriculture has been largely developed in several localities, among the chief products of which are cotton—Coahuila is the principal cotton-producing State in Mexico—Indian corn, wheat, beans, sugar and grapes. The Parras district in the southern part of the State has long been celebrated for its wines and brandies. The mineral products include silver, lead, coal, copper and iron. The mining operations are chiefly centred in the Sierra Mojada, Sierra Carmen and in the Santa Rosa valley. The mod ern industrial development of the State is due to the railway lines constructed across it during the last quarter of the 19th century, and to the investment of foreign capital in local enterprises. The first Spanish settlement in the region now called Coahuila was at Saltillo in 1586, when it formed part of the province of Nueva Viscaya. The capital of the State is Saltillo. Among the more important towns are Parras, pop. (193o) i 1,66o, 98m. W. by N. of Saltillo, one of the largest railway centres in the country, and Piedras Negras (formerly Ciudad Porfirio Diaz) on the Rio Grande.