First Annual Report on US Seafloor Mapping

 Geographic distribution and extent of the unmapped areas within U.S. ocean, coastal and Great Lakes waters. Analysis conducted in January 2020. (Credit: NOAA)
NOAA has released the first annual report on the progress made in mapping U.S. ocean, coastal and Great Lakes waters. Knowledge of the depth, shape and composition of the seafloor are foundational data elements necessary to explore, sustainably develop, understand, conserve and manage U.S. coastal and offshore natural resources. 
The 2019 Presidential Memorandum on Ocean Mapping of the United States Exclusive Economic Zone and the Shoreline and Nearshore of Alaska and the global Seabed 2030 initiative make comprehensive ocean mapping a priority for the coming decade. The “Unmapped U.S. Waters” report tracks progress toward these important goals.

“The progress made in mapping U.S. waters through 2019 represents the cumulative work of federal and state agencies, nongovernmental organizations, private contracting partners and crowdsourced contributions,” said RAdm. Shepard Smith, director of NOAA’s Office of Coast Survey. “Partnerships and advances in technology are key to making significant progress toward our common goal of completely mapping U.S. waters.”

Pulling from an analysis of publicly available bathymetry, the report presents the percentage of unmapped U.S. waters by region and shows progress toward filling these basic bathymetry data gaps with each passing year. At the end of 2019, the latest analysis yielded the following results:

Percent of U.S. waters that remain unmapped in 2019:
  • U.S. total – 54 percent of 3,592,000 square nautical miles (snm)
  • Atlantic and Gulf of Mexico – 43 percent of 472,200 snm
  • Great Lakes – 95 percent of 46,600 snm
  • Caribbean – 42 percent of 61,600 snm
  • Alaska – 72 percent of 1,080,200 snm
  • Pacific (California, Oregon, Washington) – 24 percent of 239,700 snm
  • Pacific Remote Islands and Hawaii – 50 percent of 1,691,700 snm
Multibeam and lidar surveys are the two primary sources of bathymetry needed to fill these gaps.  In support of the integrated ocean and coastal mapping goal to “map once, use many times,” all of the data collected in this effort are publicly available to benefit numerous user communities.
For the latest status on these efforts and how you can contribute, visit
The pdf version of “Progress Report: Unmapped U.S. Waters” is available at:


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