"california" originally referred to the entire region composed of the baja california peninsula now known as mexican baja california and baja california sur, and the upper mainland now known as the u.s. states of california and parts of nevada, utah, arizona, and wyoming. after mexico's independence from spain, the upper territory became the alta california province. in even earlier times, the boundaries of the sea of cortez and the pacific ocean coastlines were only partially explored and california was shown on early maps as an island. the sea of cortez is also known as the gulf of california.