By 1850, nearly 4,000,000 Americans had moved to western territories. The U.S. Homestead Act of 1862 lured even more farmers, ranchers, and minors westward, while the Transcontinental Railroad Act opened the West to trade. As the number of railroads increased, the once plentiful bison population diminished. So, too, did the ability of Plains Indians to survive on their ancestral lands. Clashes between Native Americans and U.S. troops became known as the Indian wars. The U.S. government entered into hundreds of treaties with Native Americans, yet peace was elusive. The struggle over land resulted in the relocation of the Plains Indians to reservations, where they faced an entirely new way of life.