Shipwreck records range from national inventories containing tens of thousands of wrecks to carefully documented sanctuary sites and individual coastal losses. The figures below show how wreck counts depend on geography, historical coverage, survey methods, and whether a source counts known, documented, identified, or estimated sites.
Contents
- Official inventories and risk assessments
- Shipwreck concentrations in marine sanctuaries
- Great Lakes discovery and documentation
- Historic coastal hazards and losses
- National parks and regional inventories
- Wreck fleets and wartime losses
Official inventories and risk assessments
England’s territorial sea has more than 37,000 known wrecks and recorded losses. The record represents more than 6,000 years of maritime trade, exploration, and warfare. These figures come from Historic England’s Wreck Sites at Risk, whose current inventory was reported on the page accessed September 30, 2026.
The number of protected sites is much smaller than the number of recorded wrecks. England has 57 protected wreck sites on the National Heritage List. Four of those 57 sites are on the Heritage at Risk Register. The protected-site count therefore describes a selected heritage designation rather than the size of the full wreck record.
NOAA’s Resource Protection - Potentially Polluting Wrecks in U.S. Waters gives another view of inventory scale. Its RUST database contains approximately 20,000 shipwrecks in U.S. waters. NOAA then narrowed that broad inventory to 573 vessels meeting its initial pollution-risk criteria. Additional research reduced the number posing a substantial pollution threat to 107 wrecks.
The risk-screening process produced 87 assessment packages for the U.S. Coast Guard. Within that group, six wrecks were classified as high priority for a Most Probable Discharge assessment, while 36 were classified as high priority for a Worst Case Discharge assessment.
| Inventory or screening stage | Count | What the figure represents |
|---|---|---|
| NOAA RUST database | Approximately 20,000 | Shipwrecks in U.S. waters |
| Initial pollution-risk screen | 573 | Vessels meeting initial criteria |
| Substantial pollution threat | 107 | Wrecks remaining after additional research |
| Risk-assessment packages | 87 | Packages prepared for the Coast Guard |
| Most Probable Discharge priority | 6 | High-priority wrecks |
| Worst Case Discharge priority | 36 | High-priority wrecks |
These stages should not be added together. They are successive filters applied to a large inventory, and each count answers a different management question.
Shipwreck concentrations in marine sanctuaries
Marine sanctuaries often combine a defined boundary with a mixture of known sites, documented sites, identified wrecks, and historical estimates. Stellwagen Bank National Marine Sanctuary was estimated to contain 200 wrecks in 2020. Of those estimated 200, 47 had been documented and 12 had been identified by that year. The sanctuary covers 842 square miles. NOAA’s Woods Hole Oceanographic Institution account reports those 2020 figures, while the Stellwagen Bank 2007 Condition Report says historical research indicated that more than 100 shipwrecks could lie within the sanctuary.
The different Stellwagen counts illustrate why “how many shipwrecks?” has no single answer. The estimate is the broadest figure, documentation indicates a smaller researched group, and identification is narrower still. The 2007 historical estimate and the 2020 sanctuary estimate also belong to different reporting periods.
Florida Keys National Marine Sanctuary had 14 shipwrecks listed on the National Register of Historic Places in 2011, according to NOAA’s Florida Keys 2011 Condition Report. This is a register count, not an estimate of every wreck on the seafloor.
Thunder Bay provides a Great Lakes comparison. Its original sanctuary boundary covered 448 square miles in 2013. The condition report recorded 45 known shipwrecks inside that boundary, while an expansion area under consideration contained 47 additional shipwreck sites. Historical records suggested as many as 100 undiscovered wrecks in northern Lake Huron around Thunder Bay. These categories are reported in NOAA’s Thunder Bay 2013 Condition Report.
Great Lakes discovery and documentation
The 2014 Thunder Bay sanctuary expansion increased the protected area from 448 to 4,300 square miles. By 2019, the expanded boundary contained 99 known shipwreck sites, and historical research indicated up to 100 additional undiscovered wreck sites within the expanded area. NOAA reports these figures in its Woods Hole Oceanographic Institution account; the “up to” figure is an estimate, not a confirmed inventory.
Documentation activity also has measurable scale. Thunder Bay research teams made more than 350 dives in 2011 for research and resource protection. Partners produced archaeological site maps for 24 shipwrecks in and around the sanctuary. Staff conducted field assessments at 44 of the 45 known wreck sites inside the original boundary and assessed 32 of the 47 known wrecks in the proposed expansion area. These results are described in NOAA’s Thunder Bay 2013 Condition Report.
The condition report also records shallow-water examples. The documented New Orleans wreck lay in 13 feet of water, the Shamrock wreck in 11 feet, and the Monohansett wreck in 18 feet. The collection includes an 1844 side-wheel steamer and a modern German freighter described as 500 feet long. Those measurements and vessel descriptions show the range of wreck types represented in one regional collection without implying that the sites share the same age, size, or preservation state.
Historic coastal hazards and losses
Cape Cod recorded more than 3,000 shipwrecks across 300 years of recorded history. The peninsula extends 25 miles into the ocean, placing shipping routes near its shoals. Its first recorded wreck was the Sparrow-Hawk, which ran aground in 1626. These figures and dates come from the National Park Service’s Shipwrecks - Cape Cod National Seashore.
Point Reyes has taken more than 50 ships according to the National Park Service account for Shipwrecks at Point Reyes. Before the Point Reyes lighthouse was built, more than $750,000 in ships and cargoes were lost on the rocks. One of the wrecks was the Spanish galleon San Agustin in 1595. In a separate rescue account, a Point Reyes lifesaving crew rescued all 21 people aboard the Samoa wreck without a reported serious injury. The page does not state the year of that rescue account.
Sable Island has more than 350 recorded shipwrecks since 1583, according to Parks Canada’s Archaeology - Sable Island National Park Reserve. Its first lifesaving station was established in 1801. The island is approximately 42 kilometres long and 1.3 kilometres wide at its maximum. Together, the wreck count and narrow geography explain why the island is treated as a concentrated maritime hazard, while the dates describe a record extending over centuries.
National parks and regional inventories
Dry Tortugas National Park has evidence of more than 250 marine disasters. The National Park Service says that record spans from Spanish galleons lost in 1554 to iron-hulled steamers, placing early sailing losses and later industrial vessels within the same historical landscape. The source is the NPS Stewardship of Cultural Heritage - Oceans, Coasts & Seashores.
The National Park Service identifies one 1941 shipwreck, the USS Arizona, in Hawaii in the same cultural-heritage overview. It also says divers can explore shipwrecks in more than 60 national parks with significant bodies of water, according to Diving & Snorkeling. The “more than 60” figure describes parks where wreck exploration is possible, not a total count of wrecks.
The NPS Travel Florida Shipwrecks itinerary highlights 13 historic shipwrecks listed in the National Register and accessible to divers. It covers more than 6,000 years of maritime activity around Florida. The itinerary’s 13 sites are therefore a curated, accessible subset of a much larger historical record.
The Channel Islands area inventory documented more than 140 shipwrecks and aircraft wrecks between 1853 and 1980. About 20 of those wreck sites had been located in the cited inventory, which was reported in 2008. The Channel Islands National Marine Sanctuary Final Environmental Impact Statement places the study area at approximately 1,128 square nautical miles. The inventory also records that the Winfield Scott ran aground in 1853 with more than 400 passengers aboard.
Wreck fleets and wartime losses
Mallows Bay preserves the remains of a purpose-built wartime-era fleet. Nearly 300 ships were built for the U.S. Emergency Fleet represented at Mallows Bay. Construction took place from 1917 to 1919 at more than 40 shipyards in 17 U.S. states. About 100 ships from the Mallows Bay Ghost Fleet remain in the sanctuary. These figures come from the NOAA Shipwrecks | Mallows Bay-Potomac River National Marine Sanctuary.
The Atlantic Margin wreck survey used a narrower vessel threshold. Surveys conducted from 1996 to 1998 counted 112 large wrecks in the AFEN area. The sample defined a large-vessel wreck as a ship over 60 metres long or over 1,000 gross tons. Of the AFEN-area wrecks, 24 were sunk by U-boats in the First World War and 52 were sunk by U-boats in the Second World War. The source is Appendix 4 - Seabirds Final: 4th Strategic Environmental Assessment.
The AFEN figures are survey results for vessels above an explicit size or tonnage threshold, while the Mallows Bay figures describe a particular fleet and the ships still remaining at one sanctuary. Comparing them is useful only when those scopes remain explicit: one is a regional survey, one is a constructed fleet, and neither is a global total.