SAN JUAN DE LA FRONTERA, the capital of a province of the Argentine Republic, is situated 2310 feet above the sea in a great bend of the Rio de San Juan, 95 miles north of Mendoza and 730 miles from Buenos Ayres, with which it is about to be connected by rail (1886). It is mostly built of sun-dried bricks, has a cathedral, several churches and schools, two banks, and a botanical garden, and carries on a considerable trade with Chili by the Pates and Uspallata passes. Population estimated at 20,000 (1881).

San Juan was founded in 1561 by Captain Castillo on a site 4 miles to the north, which had to be abandoned owing to inundations and is now called Pueblo Viejo. From 1776 to 1820 the city was in the government of Mendoza. President Sarmiento bestowed special attention on this his native town and gave his name to its principal school, famous throughout the republic for its excellent equipment.