Which development most influenced urban growth in western areas of the United States during the late nineteenth century?

• A. Increased immigration from East Asia
• B. The expansion of the railroad network
• C. Increased immigration from Latin America
• D. The expansion of the agricultural frontier

Answer: (B)

The main idea here is how transportation networks shape where cities form and grow. In the late 1800s, the expansion of the railroad network across the western United States opened vast areas to rapid settlement and economic activity. Railroads connected mining districts, timber and agricultural regions, and coastal markets to national and international trade routes. This created stable jobs, spurred the development of towns at railroad hubs, and directly drew people—workers, entrepreneurs, and immigrants—into these areas. As cities sprang up around railroad lines and linked western economies to the rest of the country, urban growth accelerated far more than by rural frontier expansion or isolated immigration alone. While immigration and frontier development contributed to population and activity, the railroad network was the driving force that made widespread urban growth possible in the West.