U.S. continues to close mapping gaps on ocean, coastal, and Great Lakes waters

From NOAA

In 2025, the ocean and coastal mapping community added 70,700 square nautical miles (snm) of new bathymetric data coverage to national repositories.
With an ultimate goal of fully mapped U.S.
waters by 2040, these additions brought the total down to 44% unmapped.

Progress was made on a number of fronts, but most notably in areas where regional efforts are underway to boost collaborative data acquisition activities and data sharing, in accordance with the National Ocean Mapping, Exploration and Characterization, or NOMEC, Strategy goals.

With almost 44,000 snm of new seafloor mapped, more than half of the total new bathymetry coverage gains are in the U.S. Pacific Remote Island territories and Hawaiian waters.
These bathymetric coverage gains were in predominantly deep water greater than 200 meters and conducted during expeditions funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute, including focused mapping expeditions aboard Ocean Exploration Trust’s Exploration Vessel Nautilus in 2022, 2023, and 2024 around the Hawaiian Islands, Johnston Atoll, Howland and Baker Islands, Kingman Reef, Palmyra Atoll, Jarvis Island, and American Samoa.

Adding approximately 13,000 snm of mapping data, the Alaska region, home of the Seascape Alaska campaign, saw the second largest gains in new bathymetric data coverage.
Major contributions to closing gaps in this region include NOAA Coast Survey hydrographic surveys conducted during the 2023-2025 field seasons, including multiyear projects in Kotzebue Sound and Southeast Alaska as well as an ongoing U.S. Geological Survey/NOAA co-funded mapping project south of Kodiak Island.

The Great Lakes, home of the Lakebed 2030 campaign, moved from 85% to 83% unmapped after adding approximately 1,000 snm of mapping data.
Much of that progress is attributable to NOAA multibeam sonar hydrographic surveys in Lake Michigan and eastern Lake Ontario as well as Sturgeon Bay, conducted in 2024 and 2021, respectively.
The Atlantic and Gulf region jumped from 31% to 28% unmapped during this reporting period.
Much of that progress is attributable to bathymetric LIDAR collected in Maine and Florida as well as NOAA multibeam sonar hydrographic surveys conducted during the 2023-2025 field seasons.
Conducted in 2024, the Gulf of Maine Dual Drix project represents part of this progress, focusing on testing multiple uncrewed vehicles operated from shore to improve the efficiency of mapping operations.

 

 

A map showing areas of unmapped seafloor of the United States in January 2026.
(NOAA)

 

 

A bar graph showing the percentage of unmapped seafloor at 100-meter resolution in 2025, within six regions of the United States, including the total unmapped U.S.
percentage.
(NOAA)

• Areas of U.S. waters that remained unmapped as of January 2026: U.S. total1 – 1,726,000 snm out of 3,878,700, or 44%
• Atlantic and Gulf – 155,900 snm out of 547,200, or 28%
• Great Lakes – 37,400 snm out of 45,000, or 83%
• Caribbean – 17,500 snm out of 61,500, or 28%
• Alaska2 – 781,000 snm out of 1,283,500, or 61%
• Pacific (California, Oregon, Washington) – 37,900 snm out of 249,300, or 15%
• Pacific Remote Islands and the State of Hawaii – 696,100 snm out of 1,692,200, or 41%

1. Areas include the full extent of the U.S. Continental Shelf, as declared in 88 FR 88470.
2. The unmapped portion of the U.S. Arctic waters in the Alaska region is 533,200 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 all users.
For the latest status on these efforts and how you can contribute, visit https://iocm.noaa.gov/seabed-2030-status.html.

About the annual progress report

The federal Interagency Working Group on Ocean and Coastal Mapping recently released the seventh annual report on progress made in mapping U.S. ocean, coastal, and Great Lakes waters.
To safeguard our national security and economic prosperity, ocean mapping, exploration, and characterization is foundational to maritime commerce, domestic energy and seafood production, tourism and recreation, and understanding of our natural resources, among other interests.
The 2020 National Strategy for Mapping, Exploring, and Characterizing the United States Exclusive Economic Zone (NOMEC Strategy) makes comprehensive ocean mapping a priority for the coming decade.
The Unmapped U.S. Waters report tracks progress toward these important goals.

Pulling from an analysis of publicly available bathymetry, the report presents the percentage of unmapped U.S.
waters by region and shows our progress towards resolving these basic seafloor and lakefloor mapping gaps with each passing year.
Following from the 2025 report, this 2026 report includes the U.S. continental shelf beyond the 200 nautical mile exclusive economic zone, which the U.S. proclaimed in December 2023 (88 FR 88470).
This proclamation expanded the total area of interest for mapping progress tracking from 3,590,600 square nautical miles to 3,878,700 square nautical miles.