The Californias, or Province of the Californias, or Spanish: Las Californias, Provincia de las Californias (1768–1804), was the northwestern-most area of the Viceroyalty of New Spain (comprising Spain's colonial possessions in the Western Hemisphere and Pacific Spanish East Indies).
There has been understandable confusion about use of the plural The Californias by Spanish colonial authorities. California historian Theodore Hittell offered the following explanation:
In very early times, while the country was supposed to be an island or rather several islands, it was commonly known by the plural appellation of "Las Californias" (The Californias). Afterwards, when its peninsular character was ascertained, it was called simply California; but the territory so designated was unlimited in extent. When the expeditions for the settlement of San Diego and Monterey marched, it was understood that they were going, not out of California, but into a new part of it. The peninsula then began to be generally spoken of as Antigua or Old California and the unlimited remainder as Nueva or New California, subsequently more commonly called Alta or Upper California. At the same time the old plural name of The Californias was revived, but with a more definite signification than before.
The first attempted Spanish occupation of California was by the Jesuit missionary Eusebio Kino, in 1683. His Misión San Bruno failed, however, and it wasn't until 1697 that Misión de Nuestra Señora de Loreto Conchó was successfully established by another Jesuit, Juan María de Salvatierra. The mission became the nucleus of Loreto, first permanent settlement and first administrative center of the province. The Jesuits went on to found a total of 18 missions in the lower two-thirds of the Baja California Peninsula.