<P> The Spanish colonization began the genocide of the indigenous Californian peoples, decimating their numbers through epidemics of various diseases for which the indigenous peoples had no natural immunity, such as measles and diphtheria . The establishment of the Spanish systems of government and social structure, which the Spanish settlers had brought with them, also technologically and culturally overwhelmed the societies of the earlier indigenous peoples . </P> <P> During this same period, Russian ships also explored along the California coast and in 1812 established a trading post at Fort Ross . Russia's early 19th - century coastal settlements in California were positioned just north of the northernmost edge of the area of Spanish settlement in San Francisco Bay, and were the southernmost Russian settlements in North America . The Russian settlements associated with Fort Ross were spread over an area stretching from Point Arena to Tomales Bay . </P> <P> In 1821, the Mexican War of Independence gave Mexico (including California) independence from Spain . For the next 25 years, Alta California remained as a remote, sparsely populated, northwestern administrative district of the newly independent country of Mexico . </P> <P> Cattle ranches, or ranchos, emerged as the dominant institutions of Mexican California . Soon after Mexican independence from Spain, the chain of missions became the property of the Mexican government and was secularized by 1834 . The ranchos developed under ownership by Californios (Spanish - speaking Californians) who had received land grants, and traded cowhides and tallow with Boston merchants . </P>

California is an urban state as well as one of the most diverse states in