Alta California ("Upper California") was formed in 1804 when the province of California, then a part of the Spanish colony of New Spain, was divided in two along the line separating the Franciscan missions in the north from the Dominican missions in the south. The southern part became the territory of Baja California. The two territories were also alternatively called "California Nueva" ("New California"; Upper Cal.) and "California Vieja" ("Old California"; Lower Cal.).

Alta California — covering the land occupied by the modern-day U.S. states of California, Nevada, Utah, northern Arizona and southwestern Wyoming — was recognized as one of the constituent territories of the newly independent United Mexican States with the adoption of the 1824 Constitution following its War of Independence and short-lived First Empire. During the Mexican-American War of 1846–48 U.S. Army and Navy forces invaded and captured the territory; it was formally ceded to the U.S. under the 1848 Treaty of Guadalupe Hidalgo.

The last Mexican Governor of California was Pío Pico, who served until 1846.

In the second half of the 19th century, there was a San Francisco-based newspaper called the Alta California (or sometimes the Alta Californian). Mark Twain's first widely successful book, The Innocents Abroad, was an edited collection of letters written for this publication.

Ranchos of California

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Under Spanish rule, all lands in California were claimed by the king of Spain, who granted them to the Catholic Church and to individuals. When California came under control of the Mexican government the missions were secularized and the governors gained the power to grant state lands. Few ranchos stayed intact for long, either growing or shrinking, or changing hands entirely depending on the fortunes of the owners. Some of the more famous ranchos and their descendent communities:

• Rancho la Ballona, owned by the Machado and Talamantes families
  • Venice, Marina del Rey, Playa del Rey, Inglewood, and the Ocean Park district of Santa Monica.
• Rancho Boca de Santa Monica
  
  • Santa Monica
• Rancho de las Pulgas, to Luis Antonio Argüello
• Rancho La Cañada
  • Parts of Eagle Rock, La Cañada Flintridge
• Rancho Rinconada de Los Gatos, granted in 1839 to Jose Maria Hernandez and Sebastian Fabian Peralta. 6,631 acres (27 km²)
  
  • Los Gatos, Monte Sereno
• Rancho Rosa Castilla, created by the family of Juan Batista Batz, a Basque rancher from northern Spain who settled here in the 1850s-now it's known as CSULA.
  • University Hills
• Rancho San Antonio (Lugo grant), granted 1810 by the King of Spain to Antonio María Lugo, maximum size: 29,513 acres (119 km²).
  
  • Bell Gardens, Commerce, and parts of Bell, Cudahy, Lynwood, Montebello, South Gate, Vernon and East Los Angeles.
• Rancho San Antonio (Peralta Grant), 44,800-acres granted in 1820 by Governor Pablo Vicente de Solá to Don Luís María Peralta.
  • San Leandro, Oakland, Alameda, Emeryville, Piedmont, Berkeley, and Albany.
• Rancho San Lorenzo, granted in 1841 by Governor Juan Alvarado to Guillermo Castro. 26,722 acres (108 km²)
  
  • Hayward, Castro Valley
• Rancho San Lorenzo Baja Rancho in 1842 by Governor Juan Alvarado to Francisco Soto
  
  • San Lorenzo
• Rancho San Rafael, granted 1798 by the King of Spain to José María Verdugo
  
  • Glendale, Atwater Village, Eagle Rock, Glassell Park, and Highland Park
• Rancho San Vicente y Santa Monica
  
  • Santa Monica, Brentwood
• Rancho Soscol, granted 1844 by Governor Pio Pico to Mariano Guadalupe Vallejo
  
  • Vallejo and Petaluma

See also

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For the Spanish and Mexican control of Alta California

• Spanish colonization of the Americas
• History of California
• Spanish Missions of California
• List of pre-statehood governors of California
• Presidio of Monterey, California
• Presidio of San Francisco
• El Camino Real (California)
• Island of California

For Russian colonization of Northern California

• Russian colonization of the Americas
• Fort Ross

For the transition to control by the United States

• List of pre-statehood governors of California
• Bear Flag Revolt
• Treaty of Guadalupe Hidalgo
• Treaty of Cahuenga

1804 in Mexico | Colonial Mexico | Former states of Mexico | History of California | Independent Mexico

Kalifornien (historisch) | Alta California | Alta California | 上加利福尼亞省