The Erie Canal significantly impacted the economy of the United States primarily because it opened direct trade between the Great Lakes and New York City. Completed in 1825, the canal connected the Hudson River to Lake Erie, enabling easier and more efficient transportation of goods between the interior of the country and the New York City market. This connection facilitated trade, reduced shipping costs, and allowed for the movement of larger quantities of goods, which stimulated economic growth in the regions connected by the canal and led to the rise of New York City as a major economic hub.
While the canal did influence migration and trade patterns across the country, the most direct impact related to the facilitation of trade routes and economic integration between the northern states and the Midwest. The other options mentioned do not directly pertain to the primary economic effects of the Erie Canal.