During the second half of the 1800s, the United States gained control of numerous territories in the West. Which event hastened this process?

One of the key events that hastened the United States' acquisition of territories in the West during the second half of the 1800s was the completion of the First Transcontinental Railroad. The railroad was completed in 1869 when the Central Pacific and Union Pacific rail lines met at Promontory Summit, Utah. This development facilitated westward expansion, allowing for faster and more efficient transportation of people, goods, and resources across the continent.

The railroad not only played a vital role in connecting the East and West coasts but also accelerated settlement and economic development in the western territories. It contributed to increased migration, trade, and the establishment of towns and cities along its route. As a result, the expansion and consolidation of U.S. control over territories in the West were significantly hastened during this period.