The Mapuche originally named the valley where Santa Juana is now located the Valley of Catirai, and the inhabitants Catirayen. This town originated with a fort and town in established March 1626 by Governor Luis Fernandez de Cordova with title of Santa Juana de Guadalcázar, in memory of the name of wife of the viceroy of PeruDiego Fernández de Córdoba, Marquis of Guadalcázar. Evacuated in 1641, it was repaired and expanded in 1648 by the governor Martín de Mujica y Buitrón. It was destroyed by the Mapuches in 1722, but restored two years later. In 1739 the Governor José Antonio Manso de Velasco made important adjustments, improving and properly supplying the fortress and constructing between the river and the small Laguna de Rayenantú behind it, deep ditches, that turned the enclosure into an island, and increasing its population to serve as its garrison for the defense of the region and the wooded valleys of the southern mountainous area. Governor Antonio de Guill y Gonzaga obtained the title of "Villa" for the town in 1765, but the wars with the Indians did not allow it to make any progress even though it constituted the refuge of the extinguished towns of Coya, Monterey and San Jerónimo. It was also one of the towns that was burned in 1821 at the order of Vicente Benavides the rebellious royalist guerrilla. It was later ruined in the earthquake of February 20, 1835. As a result of this last disaster the town was six years later moved to its present more suitable location. Santa Juana was head of the Department of Lautaro between 1841 and 1865. On May 30, 1865, Coronel became the new capital of the department. With the Law of Independent Communes, December 22, 1891, the Decree of Creation of Municipalities was promulgated, with which created the Municipality of Santa Juana, in which Santa Juana administers Santa Juana, Santo Domingo and San Jerónimo, whose boundaries were determined by the decrees of November 13, 1885, March 29 and December 1, 1886.
Demographics
According to the 2002 census of the National Statistics Institute, Santa Juana spans an area of and has 12,713 inhabitants. Of these, 7,095 lived in urban areas and 5,618 in rural areas. The population grew by 6.3% between the 1992 and 2002 censuses.
