Californias

Californias is a historical term that refers to Las Californias, a colonial province of New Spain along the Pacific coast. The term is used to describe the broader territory that includes what is now the U.S. state of California and the Mexican region of Baja California, with administrative usage sometimes treating Alta California (the northern portion) and Baja California (the southern portion) as distinct entities within the same province.

The name California itself originates from a 16th‑century Spanish romance in which a fictional island called California appeared. Spanish explorers adopted the toponym for the western coastal region they encountered, and the plural Californias appeared in some historical sources to denote the combined province or its two major subdivisions.

In the late 18th and early 19th centuries, Las Californias functioned as a single territorial unit of New Spain and was effectively divided into Alta California and Baja California for administrative purposes. After Mexico gained independence in 1821, the territory remained part of Mexico, though the northern portion later passed to the United States as a result of the 1848 Treaty of Guadalupe Hidalgo and became the state of California in 1850. The southern portion remained in Mexico and was later reorganized as the states of Baja California and Baja California Sur.

Today, the plural Californias is primarily of historical interest and appears mainly in discussions of colonial administration and historical cartography. In contemporary usage, the region is usually referred to as Alta California, Baja California, or simply California, depending on the context. See also Las Californias; Alta California; Baja California; California (Mexico).