Ayacucho. I. An interior central department of Peru, lying mainly on the eastern slope of the Andes, watered by the rivers Mantaro (which partly bounds it N), Pampas, and Apu-rimac; area, about 35,000 sq. m.; pop. about 150,000. Consisting partly of elevated plains and partly of deep valleys, it has a varied climate, cold in the one and excessively hot in the other. It is only partly included in the great metalliferous region; yet gold and silver are found in parts. Agriculture and bee-keeping are the principal industries; and there are many horses, cattle, sheep, llamas, and vicufias. The department derives its name from a battle fought Dec. 9, 1824, near the hamlet of Ayacu-cho, between the Spaniards and South Americans, in which the former, though 9,310 strong, while their enemies numbered only 5,780, were totally routed, with a loss of 2,000 killed, wounded, and prisoners, the South Americans losing less than a thousand. The Spanish viceroy and commander, Laserna, was captured, and on the following day Gen. Canterac, who succeeded to the command, surrendered the rest of the army in the field, Laserna signing a capitulation, which delivered up all the Spanish troops, posts, and munitions of war in Pern. The South Americans were commanded by Gen. Sucre. This battle, which lasted only a few hours, virtually secured the independence of all the Spanish possessions in South America. II. A town, the capital of the preceding department, formerly called Huamanga or Guamanga, 220 m.

S. E. of Lima, in a valley about 9,000 ft. above the level of the sea; pop. with suburbs, about 25,000. It was founded by Pizarro in 1539. The houses are generally of massive construction surrounded by gardens. The cathedral is a fine structure, and there are 23 other churches and chapels. It is one of the handsomest and most thriving cities in South America.