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United States Department of Transportation United States Department of Transportation

On National Maritime Day and Every Day, U.S. Economy Relies on Waterborne Shipping

Wednesday, May 12, 2021

In 1933, Congress declared National Maritime Day to commemorate the first transatlantic crossing under steam propulsion. BTS honors Maritime Day by observing the importance of waterborne shipping in U.S. international trade and in Americans’ everyday lives.

Maritime vessels account for 40% of U.S. international trade value, nearly 70% of trade weight, with trade of goods accounting for 18% of 2020 GDP.  

In 2020, waterborne shipping carried more tonnage (nearly 1.5 billion short tons) and value (more than $1.5 trillion) in U.S. trade than any other mode of transportation. As the chart below shows, maritime led in both imports and exports. Higher-value, light-weight cargo shipped in cargo containers accounts for most of U.S. imports, while lower-value, heavy cargo shipped in bulk contributes heavily to exports. 

Maritime industry cargo categories cover a wide range of products and commodities.

International  maritime cargo includes containerized freight such as that which was recently in the news when the container ship Ever Given got stuck in the Suez Canal.   But, maritime cargo also includes dry bulk ships for grain and other commodities, tanker ships for energy products such as crude oil and petroleum products, roll-on/roll-off (Ro/Ro) ships for cars, trucks, construction vehicles, etc., and breakbulk ships for a variety of non-containerized products, such as rolls of paper or coils of steel, and commodities, such as bags of coffee beans (often loaded on pallets). 

In 2020, U.S. ports saw more than 465,000 vessel calls, more than 10% of the global total.

Each port has its own arrangement of marine terminals serving different types of cargo. One terminal might be equipped with grain elevators to load and unload dry bulk commodities, such as coal and grains, while another uses cranes to load and unload containers, and another uses pipelines to load and unload liquid bulk cargo, such as natural gas and oil. When a ship arrives with goods to load or unload (vessel call), it uses a terminal suited for its designated cargo type. 

The map below displays the percentage of vessel calls by cargo type for the top 40 U.S. ports. For example, the Port of Houston services vessels carrying all of the cargo categories discussed above, but tankers comprise about 2/3 of all vessel calls. The Port of Duluth handles dry bulk and breakbulk, but its Minnesota neighbor, the Port of Two Harbors, only handles dry bulk. 

For more information on U.S. ports, please visit our Port Performance page.