Wanderlust World Wanderlust World Contrary to a common misconception, California was part of Mexico for 27 years (1821–1848). The transition from Spanish colony to Mexican territory resulted from three interconnected developments:
After an 11-year war, Mexico achieved independence in 1821 under the Treaty of Córdoba. As a province of the Viceroyalty of New Spain, Alta California automatically became Mexican territory. The new Mexican Empire (later Republic) inherited Spain's northern frontier, including California's missions, presidios, and pueblos.
The Mexican government, influenced by liberal ideals and seeking to break mission control over land and labor, passed secularization laws. Mission lands—vast, fertile tracts worked by Indigenous neophytes—were confiscated and redistributed as ranchos to Mexican citizens. This transferred economic power from the Church to a new class of californio rancheros, cementing Mexican civilian control.
To solidify control against foreign encroachment (Russian at Fort Ross, American and British traders), Mexico encouraged settlement. Governors issued hundreds of land grants, often to naturalized foreigners who became Mexican citizens. This influx of settlers—Mexican, American, European—integrated California into Mexico's economic and political orbit, establishing the rancho society that defined the Mexican era.
By 1846, when the U.S. invaded during the Mexican–American War, California was a functioning Mexican department with a distinct regional identity. The Treaty of Guadalupe Hidalgo (1848) transferred it to the United States, ending the Mexican period but leaving a lasting cultural imprint.