The Californias followed by Alta California
Province of New Spain
In 1767, the Jesuits were expelled from the missions, and Franciscans were brought in to take over. Gaspar de Portolá was appointed governor to supervise the transition. At the same time, a new visitador, José de Gálvez, was dispatched from Spain with authority to organize and expand the fledgling province.
The more ambitious province name, Las Californias, was established by a joint dispatch to the King from Viceroy de Croix and visitador José de Gálvez, dated January 28, 1768. Gálvez sought to make a distinction between the Antigua ('old') area of established settlement and the Nueva ('new') unexplored areas to the north. At that time, almost the only explored and settled areas of the province were around the former Jesuit missions but, once exploration and settlement of the northern frontier began in earnest, the geographical designations Alta ('upper') and Baja ('lower') gained favor.
The single province was divided in 1804, into Alta California province and Baja California province. By the time of the 1804 split, the Alta province had expanded to include coastal areas as far north as what is now the San Francisco Bay Area in the U.S. state of California. Expansion came through exploration and colonization expeditions led by Portolá (1769), his successor Pedro Fages (1770), Juan Bautista de Anza (1774–76), the Franciscan missionaries and others. Independent Mexico retained the division but demoted the former provinces to territories, due to populations too small for statehood.