Last week’s Data Vizdom broke down traffic at the busiest U.S. Great Lakes ports, showing how they handle mostly domestic traffic that facilitates internal trade. This week, we add the nuance of direction and commodities across all U.S. Great Lakes ports to see not just where goods move, but also what moves. This provides a window into the port system’s role in supporting industrial supply chains across the St. Lawrence–Great Lakes region.
The interactive chart below shows the hierarchical breakdown of traffic flows by direction for 2023, down to three levels of commodity aggregation.
Domestic traffic, shown in blue, includes interport, intraport, and inland movements. Interport refers to the movement of goods between two Great Lakes ports. Intraport captures traffic between facilities within a single port, which may span multiple locations due to how ports are defined. Inland traffic involves connections between Great Lakes ports and inland waterways. International traffic includes both inbound and outbound flows with Canada and other countries.
Across all U.S. Great Lakes ports, 70 percent of traffic is domestic, reflecting the pattern seen at the system’s busiest ports. Of this, 92 percent are movements between two Great Lakes ports, with the remainder occurring within a single port or between the lakes and inland origins or destinations. On the international side, trade with Canada far exceeds trade to and from other countries.
At the commodity level, inedible crude materials dominates both domestic and international flows. Iron ore accounts for the largest share, followed by limestone and salt. Coal and lignite are also heavily traded within the U.S. domestic market. Canada–U.S. trade shows a similar pattern: the U.S. mainly exports iron ore, limestone, and coal, while importing sand, salt, and manufactured goods such as cement and steel sheets.
For both Canada and other international partners, export volumes exceed imports. Exports to overseas markets are more diverse, with iron ore, grains, and coal making up roughly equal shares.
To conclude, the U.S. Great Lakes ports play a crucial role in moving bulk raw materials that fuel industry and trade in the St. Lawrence-Great Lakes region. Understanding the directional flows and commodity composition highlights their importance in supporting regional supply chains.
What better way to understand concepts big and small than through data visualizations? In this blog series, we explore timely themes in economics and transportation, drawing on data from the SLGL dataHub.