I. A province of Portugal, on the W. side of the kingdom, between Beira, Alemtejo, and the Atlantic ocean; area, 6,872 sq. m.; pop. in 1868, 837,451. It contains the cities of Lisbon and Leiria. It is mountainous, being traversed by the Serra da Estrella and its S. W. continuations. Its soil is watered by numerous streams, the principal of which are the Tagus and the Sadao. Grains, fruits, and wines are produced. It has suffered from earthquakes, and has unexplored mines. II. An old province of Spain, in the W. part of the peninsula, comprising the modern provinces of Badajoz and Caceres, bounded N. by Salamanca, N. E. by Avila, E. by Toledo, Ciudad Real, and Cordova, S. by Seville and Huelva, and W. by Portugal; area, 16,693 sq. m.; pop. in 1867, 733,749. It is entirely surrounded by mountains, and is divided into three parts by the rivers Tagus and Guadiana, and into two parts by the mountains of Guadalupe, San Pedro, and San Mamed. These mountains, forming but a single chain, traverse the province from E. to W., and nearly form the boundary between its two present divisions. The soil of Estremadura is very fertile, and if well cultivated would produce sufficient to support a third of the population of Spain; but nearly all the large proprietors reserve their lands for pasturage.

A little barley and wheat are cultivated, and chestnuts are abundant, forming the principal food of the inhabitants. This province is distant from the sea, and has no great highways. Even its rivers are little used for navigation. Its manufactures are of no importance, and its mines of lead, silver, and coal are neglected. It was formerly a part of the kingdom of Leon, and was the last province conquered by Alfonso IX. of that kingdom; whence the name of Estremadura, from Lat. extrema ora, last region.