Extending to the outer limits of the exclusive economic zone (EEZ) and including the U.S. continental shelf beyond the EEZ (88 FR 88470), U.S. oceans, coasts, and Great Lakes waters comprise the largest area of national seafloor and lakefloor mapping responsibility in the world at approximately 3.9 million square nautical miles. As of January 2025, 46% of U.S. waters remain unmapped, which means that either no direct measurements of the seafloor have been acquired over these areas or data has been collected and not shared for broader use. The image below shows the extent of the unmapped areas (in red) within U.S. waters.

The graph below shows how far we have progressed, since the start of this analysis in October 2017, where we reported that U.S. coastal, ocean, and Great Lakes seafloor were 59% unmapped. Based on the 2017 analysis, we needed to acquire annually new bathymetry for 161,685 square nautical miles (554,564 square kilometers) of seafloor in order to reach Seabed 2030 goals. This annual mapping goal is approximately equal to the total land area of the states of Montana and North Dakota combined (555,673 square kilometers).

In the last six years, the average annual increase in new bathymetric data coverage added to the bathymetry archive is 62,000 square nautical miles- far short of our goals. By the end of 2022, the difference between what we acquired (red bar) and what we needed to acquire to track with the Seabed 2030 timeline and goal (grey bar) is 501,100 square nautical miles of new bathymetry coverage.

Assuming that we fill bathymetry data gaps for 4% of the remaining unmapped U.S. waters each year, we are projected to have about 200,000 square nautical miles of seafloor left to map by 2033. This remaining area is approximately equal to the nearshore areas of U.S. waters that are the most difficult and time-consuming to map. To account for this challenge, we assume our rate of progress will reduce to 1% per year. This projection shows that we will complete this baseline mapping in/around 2041. It is noteworthy that this forecast is optimistic and does not take into account the numerous logistical challenges with offshore and coastal mapping.

It should be clear from these projections that we need to radically change the way we do business in order to fill the mapping gaps within U.S. waters by 2030 or 2041. This effort requires a multifaceted solution, including the acquisition of new data, making previously collected bathymetric data publicly accessible, and improvements in technology to make mapping more efficient.

Progress Reports of Unmapped U.S. Waters:

March 2025
March 2024
March 2023
March 2022
March 2021
March 2020