<P> The California Republic was short lived ; the same year marked the outbreak of the Mexican -- American War ( 1846 -- 48 ) . When Commodore John D. Sloat of the United States Navy sailed into Monterey Bay and began the military occupation of California by the United States , Northern California capitulated in less than a month to the United States forces . After a series of defensive battles in Southern California , the Treaty of Cahuenga was signed by the Californios on January 13 , 1847 , securing American control in California . </P>
<P> The California Republic was short lived ; the same year marked the outbreak of the Mexican -- American War ( 1846 -- 48 ) . When Commodore John D. Sloat of the United States Navy sailed into Monterey Bay and began the military occupation of California by the United States , Northern California capitulated in less than a month to the United States forces . After a series of defensive battles in Southern California , the Treaty of Cahuenga was signed by the Californios on January 13 , 1847 , securing American control in California . </P>
when did california become part of the usa
when did california become part of the usa
January 13 , 1847
January 13 , 1847