Santiago, Or Santiago Del Estero, a central province of the Argentine Republic, bordering on Santa Fé, Cordova, Catamarca, Tucuman, Salta, and the Gran Chaco; area, 35,000 sq. m.; pop. in 1869, 132,763. The face of the country, somewhat mountainous in the west, consists mainly of an undulating plain, sloping toward the southeast. The province is watered by the Dulce, Salado, and many smaller streams, which are dried up during the summer. There are many lagoons and lakes, mostly salt, the chief of which is the Laguna de los Porongos on the southern border, fed by the waters of the Dulce. The climate is hot, but not insalubrious; and the soil is fertile, much of the land being devoted to pasturage. The chief productions are wheat, maize, the sugar cane, and fruits. There are large forests. The most important manufactures are those of ponchos and other articles of wool, with laces, some of which are not inferior to the finest imported from Europe. Carbonate and nitrate of soda and carbonate of potash from the salines are exported. Of 33,375 children from 6 to 14 years of age in 1869, 3,684 attended school. The province is divided into 18 departments.

The capital is the city of the same name, with 7,775 inhabitants in 1869, founded about the middle of the 16th century.