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.
List of Mexican states by date of statehood
The effective independence of Mexico reached on September 27, 1821, does not meant the independence of the states, because Mexico was the only Latin American country which became independent from Spain as a monarchy. After the fall of the Mexican Empire, the Federal Republic was established on July 12, 1823.