The Californias, occasionally known as the Three Californias or the Two Californias, are a region of North America spanning the United States and Mexico, consisting of the U.S. state of California and the Mexican states of Baja California and Baja California Sur. Historically, the term Las Californias was used to define the vast northwestern region of Spanish America, as the Province of the Californias, and later as a collective term for Alta California and the Baja California peninsula.