FIGURE 2.15 Transfers of tourists, goods, investment, pollution, and immigrants between the United States and Canada. Canada and the United States have the world’s largest trading relationship. The flows of goods, money, and people across the long Canada–U.S. border are essential to both countries. However, because of its relatively small population and economy, Canada is more reliant on the United States than the United States is on Canada. All amounts shown are in U.S. dollars.