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.
Presidency of James K. Polk
The United States had been the first country to recognize Mexico's independence following the Mexican War of Independence, but relations between the two countries began to sour in the 1830s. In the 1830s and 1840s, the United States, like France and Britain, sought a reparations treaty with Mexico for various acts committed by Mexican citizens and authorities, including the seizure of American ships. Though the United States and Mexico had agreed to a joint board to settle the various claims prior to Polk's presidency, many Americans accused the Mexican government of acting in bad faith in settling the claims. For its part, Mexico believed that the United States sought to acquire Mexican territory, and believed that many Americans filed specious or exaggerated claims. The already-troubled Mexico–United States relations were further inflamed by the possibility of the annexation of Texas, as Mexico still viewed Texas as an integral part of their republic. Additionally, Texas laid claim to all land north of the Rio Grande River, while Mexico argued that the more northern Nueces River was the proper Texan border. Though the United States had a population more than twice as numerous and an economy thirteen times greater than that of Mexico, Mexico was not prepared to give up its claim to Texas, even if it meant war.