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.
1840s
The Republic of the Rio Grande declared its independence from Mexico in January 1840. However, the border with Texas was never determined (whether the Nueces River or the Rio Grande). The new Republic fought a brief and unsuccessful war for independence, returning to Mexico late in the year.