Part 4 of our series on interesting aspects of the Mexican-American War takes us to California. California is part of the Mexican War, of course, because what is now the State of California was northern Mexico at that time. While many Easterners in the U.S. talked almost mystically of the riches of California, and how it was the fairest land on the continent, the distance and the fact that it was a foreign country kept the number of U.S. settlers in Upper California very small.
John C. Frémont was an American who wanted to annex California, and hoped to do so almost single-handedly. He had been granted permission by the U.S. government to explore in the west, and was supposed to be canvassing the Disputed Area (now Oregon and Washington) in December 1845, but Frémont took his time moving through northern Mexico, dragging his feet and looking for a chance to lead his small group of armed men in an attack on the Mexican government in Upper California. He tried to start a revolution at Gavilan Peak but was told to cease and desist immediately by the U.S. consul in Upper California, Thomas Larkin. This was in early 1846, and the U.S. was not yet at war with Mexico. There was no reason to expect U.S. support for a minor insurrection begun in its name and likely doomed to failure.
Once war was declared in May, and Americans in California got word of it in June, things moved quickly. By mid-July, Sonoma, Monterey, and Yerba Buena (today’s San Francisco) were quickly occupied by American and pro-American settlers, including Frémont. The Mexican government was let down by its governor, Pío Pico, who fled, and the emboldened Americans occupied Los Angeles in mid-August. This occupation was carried out by U.S. Marines as well as settlers, but the local Mexican population was not intimidated, and launched a counter-attack under José María Flores. These Californios were unaided by the Mexican government, which was fighting U.S. forces far to the east; the Californios were defending their land from hostile occupation and seizure, and they defeated over 300 Americans, including Marines, at the two-day Battle of Dominguez Rancho in early October. In early December, Californios fought U.S. soldiers under General Stephen Kearny to a standstill near San Diego.
With the weight of the U.S. government behind the push to annex Upper California, however, the efforts of the Californios were doomed. By mid-January 1847, U.S. forces (including Frémont and his men) had won two significant battles and the majority of the remaining Californios surrendered. On January 13, 1847, the Treaty of Cahuenga was signed. This was a treaty strictly between the Californios and the U.S. military forces in Upper California, ending the fighting in Upper California. California would not change hands until the Treaty of Guadalupe Hidalgo the next year.