Mexican Cession Mexican Cession, with considerable local autonomy punctuated by several revolts and few troops sent from central Mexico, in the period from 1821–22 after independence from Spain up through 1846 when U.S. military forces seized control of California and New Mexico on the outbreak of the Mexican–American War. The northern boundary of the 42nd parallel north was set by the Adams–Onís Treaty signed by the United States and Spain in 1821 and ratified by Mexico in 1831. The eastern boundary of the Mexican Cession was the Texas claim at the Rio Grande and extending north from the headwaters of the Jojo
Mexican real ¼, ½, 1, 2, 4 and 8 reales, with gold coins for ½, 1, 2, 4 and 8 escudos. Between 1814 and 1821, copper coins were also issued for ⅛, ¼ and tlaco. During the Mexican War of Independence (1810-1821), numerous mints operated, providing coins for both the supporters and opponents of the Spanish crown. The Royalist issued coins at mints in Chihuahua, Durango, Guadalajara, Guanajuato, Nueva Viscaya, Oaxaca, Real del Catorce, San Fernando de Bexar, San Luis Potosí, Sombrerete, Valladolid Michoacán and Zacatecas. Most Royalist issues were similar in style to the earlier colonial issues from the Mexico City