Baja California Province was a province of the Spanish colonial Viceroyalty of New Spain, covering the Baja California Peninsula in present-day Mexico.
It was established in 1804, with the division of Las Californias Province into this lower Baja California Province and the upper Alta California Province (present day California).
It ceased in 1824, with the independence of Mexico from Spain, when it became Baja California Territory.
References
Baja California Province Wikipedia(Text) CC BY-SA