Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Marine Transportation

NOAA By the Numbers Topics

Marine Transportation

The U.S. marine transportation system includes 500,000 square nautical miles of navigationally significant waters. Water is the leading transportation mode for freight transported to and from the United States. NOAA National Ocean Service (NOS) is responsible for providing real-time oceanographic data, weather information, and other navigation products to promote safe and efficient navigation within U.S. waters. As ships get larger, the need for these products continues to grow. NOAA plays an important role in helping ships to avoid collisions, allisions, and groundings and in making marine transportation in the US efficient and competitive.   

NOAA's Role:

  • Precision marine navigation is the ability of a vessel to navigate safely and efficiently within U.S. waterways. It relies on foundational oceanographic, meteorological, and electronic navigational charting data; observations; predictions and forecasts; and critical maritime information.
  • NOS’s Office of Coast Survey (OCS) has been producing the nation’s nautical charts for nearly two centuries and electronic charts since the early 1990s. Specifically tailored to the needs of marine navigation, nautical charts delineate the shoreline and display important navigational information, such as water depths, prominent topographic features and landmarks, and aids to navigation. They represent one of the most fundamental tools available to mariners. 
    • NOAA electronic navigational charts (NOAA ENC®) are NOAA’s primary nautical chart product. Originally designed for large commercial vessels using a sophisticated navigational computer called an electronic chart display and information system (ECDIS), ENCs are now also used on simpler navigation systems on many types of ships and by recreational boaters.
  • NOS’s Center for Operational Oceanographic Products and Services (CO-OPS) provides accurate, reliable, and timely tides, water levels, currents, and other coastal oceanographic and meteorological information. CO-OPS maintains ocean observing infrastructure, through systems such as NWLON and PORTS®. These systems provide the nation with historic and real-time data, forecasts, predictions, and scientific analyses that protect life, the economy, and the environment on the coast.
    • The National Water Level Observation Network (NWLON) is an observation network with more than 200 permanent water level stations on the coasts and Great Lakes. This system allows NOAA to provide the nation with official tidal predictions. Accurate water level data is critical for safe and efficient marine navigation and for the protection of infrastructure along the coast. The NWLON also provides the national standards for tide and water level reference datums used for nautical charting, coastal engineering, international treaty regulation, and boundary determination. 
    • Physical Oceanographic Real-Time System (PORTS®) is a decision support tool that improves the safety and efficiency of maritime commerce and coastal resource management through the integration of real-time environmental observations, forecasts and other geospatial information. PORTS® measures and disseminates observations and predictions of water levels, currents, salinity, and meteorological parameters (e.g., winds, atmospheric pressure, air and water temperatures) that mariners need to navigate safely.
    • Additional information on NOAA’s marine navigation products and services can be found here.

Why It Matters

  • According to the Marine Economy Satellite Account report, in 2023 there were 2.5 million jobs in the U.S. Marine Economy with 302,000 jobs within the transportation and warehousing industry alone. Within the transportation and warehousing industry there were 48,000 jobs in water transportation. The marine economy generated $827 billion in gross output (2023$). Of that, $111 billion was attributable to the transportation and warehousing industry, including $51 billion in the water transportation industry. – U.S. Bureau of Economic Analysis. (2025). Marine Economy Satellite Account, 2023. https://www.bea.gov/data/special-topics/marine-economy
  • U.S. ports are located throughout the country and are critical for the U.S. economy. In 2024, they accounted for 41 percent of all U.S. imports and exports, totaling over $2.1 trillion. In addition, waterborne transportation and its support activities employed 164,900 people in the United States, with a total annual payroll of $13.5 billion in 2024. – United States Department of Transportation, Bureau of Transportation Statistics. (2026). Port Performance Freight Statistics: 2026 Annual Report. Washington, DC: 2026. https://doi.org/10.21949/1403522 
  • Precision navigation technology plays a key role in allowing large ships with reduced under keel clearance to safely and effectively navigate U.S. ports. A 2020 NOAA study of the effects of implementing precision navigation technology found that providing an extra foot of draft in the ports of the Lower Mississippi could lead to a decrease of $200 million – $440 million in operation costs for ships. For the Port of New York/New Jersey an extra foot of draft would lead to $216 million – $472 million reduction in operating expenses. – Eastern Research Group. (2020). Precision Navigation Socioeconomic Study, report prepared for NOAA Office of Coast Survey, Lexington, MA. https://nauticalcharts.noaa.gov/learn/docs/precision-navigation/precision-navigation-socioeconomic-study.pdf
  • The NOAA Physical Oceanographic Real-Time System (PORTS®) decreases vessel transits by maximizing the use of channel depths, reduces vessel transit delays, enhances oil pollution remediation efforts, reduces commercial and recreational marine accidents (collisions, allisions, and groundings), and enhances commercial fishing. The annual benefit of implementing PORTS® at the 175 busiest U.S. seaports was estimated to be $300 million (2010$). – Wolfe, K. Eric and MacFarland, David. (2016). A Valuation Analysis of the Physical Oceanographic Real Time System (PORTS). Journal of Ocean and Coastal Economics: Vol. 3: Iss. 1, Article 12. https://doi.org/10.15351/2373-8456.1058 ; Wolfe, Eric and Mitchell, Kenneth N. (2018). Allisions, Collisions and Groundings: Estimating the Impact of the Physical Oceanographic Real Time System (PORTS(R)) on Accident Reduction. Journal of Ocean and Coastal Economics: Vol. 5: Iss. 1, Article 4. https://doi.org/10.15351/2373-8456.1091