cheyhendrix cheyhendrix 12-06-2017 History contestada During the second half of the 1800s, the United States gained control of numerous territories in the West. Which event hastened this process? massacre of American Indians at Wounded Knee in 1890 passage of the Compromise of 1850 US victory in the Mexican-American War in 1848 discovery of gold in the Klondike in 1896