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.
Mexico
In 1813 the Congress of Chilpancingo was convened and, on November 6, signed the "Solemn Act of the Declaration of Independence of Northern America". Morelos was captured and executed on December 22, 1815.
In subsequent years, the insurgency was near collapse, but in 1820 Viceroy Juan Ruiz de Apodaca sent an army under the criollo general Agustín de Iturbide against the troops of Vicente Guerrero. Instead, Iturbide approached Guerrero to join forces, and on August 24, 1821 representatives of the Spanish Crown and Iturbide signed the "Treaty of Córdoba" and the "Declaration of Independence of the Mexican Empire", which recognized the independence of Mexico under the terms of the "Plan of Iguala".