The whole states of California, Nevada, Utah and Texas, as well as parts of Wyoming, Colorado, Oklahoma, Arizona, New Mexico and Kansas.At the end of the Mexican-American War (1846-1848) Mexico lost present-day California, Nevada, Utah, part of Colorado as well as most of northern New Mexico and Arizona. Also at the end of the war Mexico was forced to cease any attempt on reclaiming Texas, which at the time included present-day Texas, as well as those parts of Oklahoma, Kansas, Colorado and Wyoming described above. This is also known as the Mexican Cession (1848).