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
History of Hispanic and Latino Americans in the United States from Nacogdoches traded with the French and Anglo residents of Louisiana, and were culturally influenced by them. The third settlement was located North of the Rio Grande toward the Nueces River. These Southern ranchers were citizens of Spanish origin from Tamaulipas and Northern Mexico, and identified with both Spanish and Mexican culture. 1821, Agustin de Iturbide launched a drive for Mexican Independence. Texas became a part of the newly independent nation without a shot being fired. In 1821 at the end of the Mexican War of Independence, there were about 4,000 Tejanos living in what is now the state of