Contra Costa County, California
In 1821 Mexico gained independence from Spain. While little changed in ranchero life, the Mexican War of Independence resulted in the secularization of the missions with the re-distribution of their lands, and a new system of land grants under the Mexican Federal Law of 1824. Mission lands extended throughout the Bay Area, including portions of Contra Costa County. Between 1836 and 1846, during the era when California was a province of independent Mexico, the following 15 land grants were made in Contra Costa County.
Oxnard Plain
Mexico gained its independence from Spain in 1821. With the secularization of the missions by the Mexican government in June 1836, their lands were granted as rewards for loyal service or in response to petitions by individuals. Most of the arable land was divided up into large ranchos by 1846. This opened up the Oxnard Plain to further settlement by Europeans. Control of the area was transferred to the United States under the Treaty of Guadalupe Hidalgo in 1848 and California became the 31st state in the Union in 1850. Many Mexican residents and residents who had immigrated from European countries became U.S. citizens.