After the Civil War, the arrival of Anglo-Americans proved disastrous for the people and the cultures west of the Mississippi. The most widespread Indian presence in the West was the Plains Indians. Their cultures were based on close and extended family networks and on an intimate relationship with nature. Many of these nations, including the powerful Sioux, subsisted largely through hunting buffalo. Although many tribes did not unite against white settler encroachment on their lands, the Sioux, Arapaho and Cheyenne did form a powerful alliance in the northern plains. However, many Native Americans remained vulnerable to eastern infectious diseases and at a considerable disadvantage in any long-term battle with an economically and industrially advanced people - they were outnumbered and outgunned by easterners wanting to encroach on their land. After the Civil War, the U.S. Army directed its efforts to taking over the Spanish/Mexican settlement in TX, the Southwest and CA. Centuries old Spanish mission society was largely reduced. It also broke the power of the the Navajo, Apache and other tribes. Chinese migration after 1848... In 1869, the transcontinental railroad was completed.The establishment of "Chinatowns" and anti-Chinese sentiments...The Chinese Exclusion Act... The Homestead Act... The admission of new states between 1864 - 1896: Nebraska, Colorado, North and South Dakota, Montana, Washington,Wyoming, Idaho, Utah, Arizona, New Mexico and Oklahoma... The western mining boom 1860 - 1890s...