Maritime archaeology statistics show an enormous and uneven archaeological record beneath seas, lakes and rivers. Official inventories range from nearly 70 known wrecks in Lake Ontario National Marine Sanctuary to more than 37,000 known wrecks and recorded losses in England’s territorial sea. The figures below retain each source’s geography, definition and measurement period, so they should be compared as local baselines rather than added into a single global total.
Contents
- International governance and scope
- Shipwreck inventories and protection baselines
- Regional site distributions
- Discoveries, surveys and fieldwork
- Conservation assessment and archaeological risk
- Public access and participation
International governance and scope
The international legal framework provides a useful starting point for understanding what counts as underwater cultural heritage. The UNESCO Underwater Cultural Heritage 2001 Convention had 81 States Parties in 2026. The convention framework covers cultural, historical or archaeological objects immersed for at least 100 years. That threshold is a definition of the convention’s scope, not a claim that every submerged object older than a century has been found or formally protected.
UNESCO’s 2026 page reports 12 missions by its Scientific and Technical Advisory Body. It also reports 28 capacity-building sessions delivered across four regions, reaching more than 450 participants. These figures describe international cooperation and training activity, not the number of archaeological sites. They also show why maritime archaeology statistics include institutional measures alongside wreck counts: governance capacity affects how much of the underwater record can be documented and managed.
Shipwreck inventories and protection baselines
Large inventories are often starting points for risk assessment rather than complete archaeological censuses. NOAA’s Resources and Undersea Threats database includes approximately 20,000 shipwrecks in U.S. waters on its current assessment page. Under a 2010–2020 assessment program, initial criteria narrowed that broad inventory to 573 candidates for pollution-risk assessment. Additional research identified 107 U.S. wrecks posing a substantial pollution threat, and NOAA produced 87 individual wreck-specific risk assessments. Congress appropriated $1 million in 2010 for NOAA to identify ecologically and economically significant potentially polluting wrecks in U.S. waters.
Older regional records illustrate how charting and inventory definitions can differ. The SEA 6 Archaeology report recorded 3,162 shipwreck and obstruction records in the SEA 6 area in its 2003 baseline. Of those, 1,744 were charted and 1,418 were uncharted. The same report recorded more than 3,000 wrecks in Northern Ireland’s shipwreck database and at least 1,163 wrecks around the Isle of Man. These are historical baseline figures and should not be presented as current inventories.
For England, Historic England’s wreck-site information reports more than 37,000 known wrecks and recorded losses in England’s territorial sea. The record represents more than 6,000 years of maritime trade, exploration and warfare. England had 57 wrecks designated as protected wreck sites on its National Heritage List in 2026. The contrast between more than 37,000 known records and 57 protected designations demonstrates the difference between recording, legal designation and active management.
Regional site distributions
National marine sanctuaries provide several detailed regional snapshots, but their boundaries and inventory methods vary.
| Place or program | Reported archaeological baseline | Period or status |
|---|---|---|
| Lake Ontario National Marine Sanctuary | Nearly 70 historic shipwrecks; 1 historic aircraft | Current page accessed 2026 |
| Papahānaumokuākea Northwestern Hawaiian Islands | 60 shipwrecks reported lost; 17 discovered and documented | Through current inventory |
| Monterey Bay National Marine Sanctuary | 463 vessel and aircraft losses | Current sanctuary record |
| Thunder Bay National Marine Sanctuary | More than 200 shipwrecks | Current sanctuary record |
| Wisconsin Shipwreck Coast | 36 protected shipwrecks; nearly 60 additional wrecks estimated undiscovered | Current designation record |
| Mallows Bay-Potomac River | More than 100 World War I-era wooden steamship remnants | Current protection |
The Lake Ontario National Marine Sanctuary shipwreck record lists nearly 70 known historic shipwrecks and one known historic aircraft. In Papahānaumokuākea, 60 shipwrecks are reported lost in the Northwestern Hawaiian Islands, while NOAA maritime archaeologists have discovered and documented 17 of those sites.
The NOAA maritime heritage locations overview records 463 vessel and aircraft losses on the seabed of Monterey Bay National Marine Sanctuary. Thunder Bay preserves more than 200 shipwrecks in Lake Huron. Wisconsin Shipwreck Coast protects 36 shipwrecks across 962 square miles, while historical research suggests nearly 60 additional shipwrecks remain undiscovered there. Channel Islands National Marine Sanctuary and National Park saw more than 150 historic ships and aircraft wreck between 1853 and 1980. Greater Farallones National Marine Sanctuary may contain over 400 reported ship and aircraft wrecks. Mallows Bay-Potomac River protects the remnants of more than 100 World War I-era wooden steamships.
The Florida Keys National Marine Sanctuary heritage assessment estimates that about 2,000 shipwrecks may have occurred in the Florida Keys since European exploration of the Western Hemisphere. This is an estimate across a long historical period, not a count of located sites.
Discoveries, surveys and fieldwork
The Florida Keys figures show how archival research and field investigation produce different kinds of evidence. Research completed for the sanctuary produced approximately 669 accounts of ship losses. Field investigations after the sanctuary’s 1990 designation produced more than 400 physically recorded sites, and shipwreck field projects produced 38 reports. The distinction matters: an account of a loss, a physically recorded site and a completed report are separate measures.
The sanctuary’s collaborative underwater-resource documentation involved 122 projects and 996 individuals from approximately 1995–2025. The Florida Keys maritime heritage program also describes the region’s maritime history as spanning 500 years. Together, these measures capture the scale of participation and documentation without implying that all historical loss accounts correspond to located wrecks.
Parks Canada’s 2024–25 departmental results report gives a concentrated example from the wrecks of HMS Erebus and HMS Terror. After the wreck locations were confirmed, the underwater archaeology program completed 14 archaeological projects between 2008 and March 2025. The team made 747 individual dives at the two wrecks. Targeted Erebus excavations occurred during four field seasons: 2019 and 2022–2024.
Parks Canada recovered 1,558 artefacts from Erebus since 2014. As of March 2025, it had recovered 0 artefacts from Terror. That zero is a time-bounded recovery figure, not evidence that Terror lacks archaeological material. It indicates only the reported recovery status through March 2025.
A different historical dataset appears in the NOAA repository study on underwater cultural heritage in the Pacific. The Manila Galleon study covers 400 known voyages between 1565 and 1815 and identifies approximately 59 shipwrecks among those voyages. NOAA also reports that it rediscovered the 523-foot USNS Mission San Miguel wreck in 2015. Voyage totals, historical wreck estimates and modern rediscoveries represent different stages in the archaeological research process.
Conservation assessment and archaeological risk
Condition surveys show how inventories become management decisions. The Thunder Bay National Marine Sanctuary Condition Report reports that NOAA staff conducted field assessments at 44 of 45 known shipwreck sites within the sanctuary’s current 448-square-mile boundary in a 2023 condition report. In the proposed expansion area, NOAA assessed 32 of 47 known wreck sites. Sanctuary staff and partners also produced archaeological site maps for 24 shipwrecks in and around the sanctuary.
These assessment figures are tied to the 2023 report and should not be read as a complete census of every wreck in Lake Huron. The current Thunder Bay boundary covers 448 square miles, while the regional sanctuary record describes more than 200 preserved shipwrecks. The two figures use different reporting contexts: one describes a sanctuary boundary and survey sample, while the other describes a broader preserved-wreck baseline.
Pollution risk is another conservation category. NOAA’s U.S. assessment program began with approximately 20,000 shipwrecks, screened 573 candidates, identified 107 substantial pollution threats and produced 87 individual risk assessments. Those stages should remain separate because they measure inventory size, screening, threat identification and completed assessment outputs.
In England, Historic England’s Wreck Sites at Risk page lists 4 English protected wreck sites on the Heritage at Risk Register in 2026. The Florida Keys heritage assessment lists 14 shipwrecks on the U.S. National Register of Historic Places, along with 2 lighthouses. These designations indicate recognized heritage status; they do not mean that all other recorded sites lack archaeological value.
Public access and participation
Legal protection and public access overlap only partly. Of England’s 57 protected wrecks, 6 currently have protected-wreck dive trails or can be visited above water, according to Historic England. Access therefore reaches a small, specifically interpreted subset of the protected-wreck list.
The Florida Keys Shipwreck Trail provides interpretation for 9 distinct shipwreck sites. Those 9 sites represent 3 broad periods: European Colonial, American and Modern/World War II. The trail is an interpretation network, so its count should not be confused with the sanctuary’s approximately 2,000 estimated historical wreck losses or more than 400 physically recorded sites.
At the system level, NOAA describes its national marine sanctuaries and marine national monuments as 600,000 square miles of underwater parks available for exploration. NOAA’s Maritime Heritage Program archaeology page, revised in 2023, states that 13 national marine sanctuaries contain diverse archaeological sites. The same page described the Northwestern Hawaiian Islands reserve as being in designation to become the 14th national marine sanctuary; that statement is retained with its original page context rather than treated as a later status update.
Taken together, these statistics describe maritime archaeology as a chain of work: defining underwater heritage, recording losses, locating sites, assessing condition, protecting selected wrecks and building ways for the public to encounter them. The counts remain most useful when their dates, boundaries and meanings stay visible.