Types of Ports

Each and every port has a unique arrangement and number of marine terminals. For example, one terminal may be equipped with grain elevators to unload/load dry bulk commodities, such as coal and grains transported by dry bulk vessel, while another uses ship-to-shore gantry cranes to unload/load container cargo from containerships or pipelines to unload/load liquid bulk cargo, such as natural gas and oil from tankers.
Observed vessel entrances and ship type provide a means for identifying the type of cargo handled by a port. Each category of waterborne cargo requires a particular type of vessel and marine terminal. A port's marine terminals must have the necessary cargo handling equipment and supporting intermodal infrastructure. This program covers five major categories of waterborne cargo:
  1. Containerized
  2. Dry Bulk
  3. Liquid Bulk
  4. Break Bulk
  5. Roll-on/Roll-off (Ro/Ro)
As shown for select ports in the following figure, container vessels predominantly call at ports with marine terminals having good road and rail connections, mostly along the Nation's Atlantic and Pacific coasts. Dry bulk vessels primarily call at ports that are located near iron ore deposits along the Great Lakes or located near the farms growing food and farm products along the Mississippi River System. Ports like Baltimore, Jacksonville, and Tacoma handle a sizeable share of Ro/Ro vessels.[1]
Tankers call at ports with liquid bulk terminals that have pipeline connections or refineries located nearby. These marine terminals are primarily located at ports along the Gulf of Mexico. According to the U.S. Energy Information Administration, nearly half of total U.S. petroleum refining capacity is located along the Gulf coast as is more than half of U.S. natural gas processing plant capacity. Further, the states in this region have dense concentrations of interstate and intrastate crude oil, gas, and petroleum product pipelines.[2]
Another way to look at port type is by port governance. Port governance influences cargo operations and investment decisions. Ports are organized and governed in several ways, each of which has implications for port definitions and data availability. Most ports in the United States are special district governments, followed by ports owned by state, county, or municipal governments. 
Special districts (also known as port districts) are authorized by Federal or State law to provide only one or a limited number of designated functions and with sufficient administrative and fiscal autonomy to qualify as separate governments (e.g., the Philadelphia Regional Port Authority, Lake Charles Harbor District, Mid-America Port Commission). Municipal governments are local governments (also known known as cities and towns) authorized in state constitutions and established to provide general government for a defined area (e.g., the Port of Los Angeles is an agency within the City of Los Angeles).[3]
[1] U.S. Department of Transportation, Bureau of Transportation Statistics analysis, based upon automatic identification system (AIS) data from the U.S. Coast Guard’s Nationwide Automatic Identification System (NAIS) archive, processed using the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory's AIS Analysis Package (AISAP) software package.
[2] U.S. Energy Information Administration, Gulf of Mexico Factsheet, available at https://www.eia.gov/special/gulf_of_mexico/ as of August 2022.
[3] U.S. Department of Transportation, Bureau of Transportation Statistics analysis, based upon the U.S. Census Bureau, Census of Government 2017, available at https://www.census.gov/programs-surveys/cog.html as of August 2022.