By the late 1880's and 1890's, the west had been settled by the United States. The U.S. stretched from the Atlantic Ocean to the Pacific Ocean. The California Gold Rush, Colorado Gold and Silver Rushes, railroads, grazing land for cattle and sheep, and the dream of owning your own land helped speed up the settling of the west. Native American tribes had been killed or moved to reservation lands that were very difficult for anyone to live on. In 1912, New Mexico and Arizona changed from territories and became the last states in the continental U.S. to join the union.