La Pampa, a territory of the southern pampa region of Argentina, bounded N. by Mendoza, San Luis and Cordoba, E. by Buenos Aires, S. by the territory of Rio Negro, from which it is separated by the river Colorado, and W. by Mendoza. Pop. (1904, official estimate), 52,150. It belongs geographically to the southern part of the great Argentine pampas, from which its name is derived, but in reality only a part of its surface belongs to the plain region. The western and southern part (perhaps the larger) is much broken by hills, swamps and sandy wastes, with occasional stretches of wooded country. The western half is crossed by a broad depression, extending from Mendoza southeast to an intersection with the valley of the Colorado, which was once the outlet of the closed drainage basin occupied by the provinces of Mendoza, San Juan and San Luis. This depression is partially filled with swamps and lakes, into which flow the rivers Atuel and Salado. An obscure continuation of these rivers, called the Chadi-leubu, flows south-east from the great swamps into the large lake of Urrelauquen, about 60 m. north of the Colorado. There are a great number of lakes in La Pampa, especially in the south-east. The eastern half is described as fertile and well adapted for grazing, although the rainfall is very light. Since the closing years of the Toth century there has been a large emigration of stock-raisers and agriculturists into La Pampa, and the territory has become an important producer of cattle and sheep, wheat, Indian corn, linseed, barley and alfalfa. The climate is excessively dry, and the temperature ranges from the severe frosts of winter to an extreme of 104° F. in summer. Strong, constant winds are characteristic of this region. Railways have been extended into the territory from Buenos Aires and Bahia Blanca, the latter being the nearest seaport. There is connexion also with the Transandine railway line on the north. The capital is General Acha (pop. about 2000 in 1905), and the only other places of importance are Santa Rosa de Toay and Victorica, both small, uninteresting "camp" villages.