Final answer:
The completion of railroads in the Washington territory helped form a national market system and attract immigrants to work in factories, boosting economic development and fueling industrial and urban growth.
Step-by-step explanation:
The completion of the railroads in the Washington territory significantly boosted economic development in several ways. First, the railroads facilitated the emergence of a national market system, allowing goods and resources to move more efficiently across the country.
For example, vast mineral resources in the western states could now be transported to manufacturing hubs, fueling the growth of different industries, such as steel manufacturing. This connectivity directly supported industrial expansion and urbanization.
Another key impact of the completed railroads was the attraction of immigrants. After the civil war, the United States saw an influx of fourteen million immigrants who came to work in factories.
This labor force was crucial for the burgeoning industries and contributed to the transformation from a rural to an urban society. It also encouraged the growth of labor unions, as factory conditions often required improvement.