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.
Treaty of Córdoba
On September 27, 1821, the Army of the Three Guarantees entered triumphantly into Mexico City and on the following day, the Declaration of Independence of the Mexican Empire was widely known. The Spanish Cortes refused to accept the validity of the Plan of Iguala or the Treaty of Córdoba. Spain did not recognize Mexico's independence until December 1836. Therefore, the Mexican Congress elected a Mexican monarch the following year. Iturbide was proclaimed emperor of Mexico on May 18, 1822. The monarchy lasted three years, and after the republican revolution of Casa Mata, the Congress no longer considered the Plan of Iguala or Treaty of Córdoba in effect.