This paper attempts to prove that the Pikes Peak gold rush was the impetus that drastically altered the culture and lifestyle of the Plains Indians, particularly the Cheyenne and Arapaho tribes. Special attention is given to the introduction of agriculture, the increasing dependence on government annuities, and the demise of warrior culture. These three changes characterized life on a reservation. Due to the erosion of their traditional way of life, living conditions on the Cheyenne and Arapaho reservation were very low. This paper will also attempt to prove that the reservation life imposed on the natives prompted many of them to adopt the educational, vocational, and social habits of whites. Some accomplished this by attending white schools and learning English, while others simply moved off the reservation and assimilated into European-American society.