Maritime history is preserved in shipwrecks, historic vessels, protected seascapes, and the communities that depend on marine waters. Across U.S. national marine sanctuaries and maritime parks, official records document hundreds of wrecks, thousands of square miles of protected water, and vessels built across more than a century of American working-waterfront history.
Contents
- Shipwreck statistics in the Great Lakes
- Mallows Bay and the Ghost Fleet
- Pacific coast maritime heritage
- Sanctuary size and historical scope
- The national marine sanctuary system
- Maritime economies and coral reef protection
- Historic vessels in San Francisco
Shipwreck statistics in the Great Lakes
The Great Lakes contain some of the most concentrated and well-documented maritime history in the United States. NOAA’s Thunder Bay National Marine Sanctuary spans 4,300 square miles and has 99 known shipwrecks. NOAA also reports more than 100 shipwrecks yet to be located there. Fire, ice, collisions, and storms have claimed more than 200 vessels in and around Thunder Bay. The sanctuary was designated in 2000 and expanded in 2014.
The site’s interpretive infrastructure is substantial. Thunder Bay’s Great Lakes Maritime Heritage Center contains 10,000 square feet of immersive exhibits, giving visitors a physical setting in which to understand the wrecks and the conditions that produced them. These figures describe a maritime landscape that includes both documented archaeological resources and a much larger estimated or anticipated record beneath the water.
Lake Ontario National Marine Sanctuary provides another view of Great Lakes preservation. NOAA’s about page lists 41 known shipwrecks and one known aircraft. Historical records suggest that 19 additional shipwrecks and three additional aircraft may be in the Lake Ontario area. The sanctuary spans 1,722 square miles, and its history extends across more than 200 years.
NOAA’s 2025 Lake Ontario feature uses a broader count, describing 63 known shipwrecks and one known submerged aircraft. Because these counts come from different NOAA pages and periods of presentation, they should be read as reported figures tied to their respective sources, rather than combined into a single total. The distinction matters in maritime history, where surveys, boundary definitions, and newly documented sites can change the number associated with a place.
Wisconsin Shipwreck Coast National Marine Sanctuary includes 36 known shipwreck sites across 962 square miles. NOAA reports that 27 Wisconsin shipwrecks are listed on the National Register of Historic Places, while research suggests another 60 may yet be discovered. The comparison below separates currently known or designated resources from possible future discoveries.
| Great Lakes location | Protected area | Known or listed resources | Additional possibilities |
|---|---|---|---|
| Thunder Bay | 4,300 sq. mi. | 99 known shipwrecks | 100+ not yet located |
| Lake Ontario | 1,722 sq. mi. | 41 known shipwrecks; 1 aircraft | 19 shipwrecks; 3 aircraft suggested by records |
| Wisconsin Shipwreck Coast | 962 sq. mi. | 36 known sites; 27 on the National Register | About 60 may yet be discovered |
Mallows Bay and the Ghost Fleet
Mallows Bay-Potomac River National Marine Sanctuary covers 18 square miles and contains 141 known shipwrecks. NOAA reports that Mallows Bay holds the remains of more than 100 wooden steamships, while the collection represents more than three centuries of American history. The area was nationally recognized by the National Park Service in April 2015.
The site’s historical depth reaches further back than the shipwreck collection alone. NOAA reports that Mallows Bay heritage dates back nearly 12,000 years. That span places the modern wrecks within a much longer record of human activity connected to the Potomac River landscape.
The World War I-era vessels are often described as the Ghost Fleet. NOAA’s National Marine Sanctuaries background page says the fleet consisted of more than 100 wooden steamships. A NOAA news account of the agency’s 2019 Mallows Bay celebration identified 118 World War I-era wooden steamships. These are source-specific descriptions: the broader background statement and the 2019 celebration account should remain distinct rather than being treated as duplicate measurements.
Mallows Bay therefore combines several kinds of maritime statistics: 141 known shipwrecks for the sanctuary, more than 100 wooden steamships in the bay’s remains, 118 World War I-era wooden steamships identified in the 2019 account, and nearly 12,000 years of heritage. Together, the figures show why a maritime site can be historically important even when its footprint is relatively small.
Pacific coast maritime heritage
Pacific coast sanctuaries record losses across open ocean, offshore islands, and historically active coastal routes. NOAA reports that more than 150 historic ships and aircraft wrecked in the Channel Islands between 1853 and 1980. The Channel Islands National Marine Sanctuary protects 1,470 square miles of ocean waters.
The Monterey Bay maritime heritage region has a recorded 463 vessel and aircraft losses, according to NOAA’s “Where to Experience Maritime Heritage” material. Greater Farallones has more than 400 reported ship and aircraft wrecks and encompasses 3,295 square miles. NOAA’s Greater Farallones condition report says the sanctuary was designated in 1981 and expanded to its current size in 2015.
Olympic Coast has approximately 200 historical shipwrecks reported in its vicinity. A separate NOAA Maritime Heritage Resource Management Guidance document says 150 shipwrecks formed the basis for the Olympic Coast Maritime Heritage Database. As with the Lake Ontario figures, these counts represent different NOAA descriptions and should not be added together without a defined method.
Chumash Heritage National Marine Sanctuary covers 4,543 square miles and stretches nearly 60 miles from shore. It includes 116 miles of coastline, and NOAA documents more than 200 shipwrecks in the region. The combination of offshore distance, coastline, and wreck count illustrates how maritime heritage extends across both submerged sites and the coastal geography that shaped navigation.
Sanctuary size and historical scope
Protected-area statistics make it possible to compare the physical scale of maritime history sites. The areas reported by NOAA range from Mallows Bay’s 18 square miles to thousands of square miles in the Great Lakes and Pacific Ocean. Area alone does not measure the number or importance of wrecks, but it helps define the geographic setting in which maritime resources are managed.
| Sanctuary or region | Reported area | Reported heritage measure |
|---|---|---|
| Mallows Bay-Potomac River | 18 sq. mi. | 141 known shipwrecks |
| Lake Ontario | 1,722 sq. mi. | 41 known shipwrecks and 1 aircraft on NOAA’s about page |
| Greater Farallones | 3,295 sq. mi. | 400+ reported ship and aircraft wrecks |
| Thunder Bay | 4,300 sq. mi. | 99 known shipwrecks; 100+ yet to be located |
| Chumash Heritage | 4,543 sq. mi. | 200+ documented shipwrecks |
The Chumash Heritage sanctuary also stretches nearly 60 miles from shore and includes 116 miles of coastline, while Channel Islands protects 1,470 square miles of ocean waters. Those linear measurements add context that a square-mile total cannot provide: maritime heritage is distributed along shorelines, across nearshore waters, and farther offshore.
The national marine sanctuary system
NOAA says the National Marine Sanctuary System protects more than 620,000 square miles of marine and Great Lakes waters and contains 18 underwater parks. These system-wide figures establish the national scale within which individual sanctuary histories are preserved.
The system’s size has changed over time. A NOAA press release dated September 5, 2002, said that 13 national marine sanctuaries encompassed more than 18,000 square miles. That historical figure belongs to the system as described in 2002 and should not be presented as a current total. The later system-wide figure of more than 620,000 square miles reflects a different reporting period and scope.
Designation dates also mark the development of marine heritage protection. Key Largo National Marine Sanctuary was designated on December 18, 1975, and Looe Key National Marine Sanctuary was designated on January 16, 1981. Greater Farallones was designated in 1981, while Thunder Bay was designated in 2000. Mallows Bay’s national recognition by the National Park Service came in April 2015, and Greater Farallones reached its current size after an expansion in 2015. These dates describe milestones in protection and recognition, not the age of the wrecks themselves.
Maritime economies and coral reef protection
The Florida Keys figures show that maritime history and marine protection are connected to living communities and regional economies. NOAA reports that Florida Keys waters support more than 77,000 residents and receive up to 5.5 million visitors annually. The Florida Keys economy is nearly $5.0 billion, with approximately 60% tied directly to marine-related activities.
NOAA also reports the historical scale of two protected coral reef areas. Key Largo National Marine Sanctuary protected 103 square nautical miles of coral reef habitat, while Looe Key National Marine Sanctuary protected 5.32 square nautical miles. These areas were designated on different dates: Key Largo on December 18, 1975, and Looe Key on January 16, 1981.
The Florida Keys statistics are not shipwreck counts, but they broaden the meaning of maritime history and protection. They place historic and ecological marine resources within a region measured not only by submerged habitat, but also by residents, visitors, and economic activity connected directly to the water.
Historic vessels in San Francisco
Maritime history is also preserved through vessels that remain accessible as historic objects. San Francisco Maritime National Historical Park maintains six historic ships, according to the National Park Service. Five of those ships are National Historic Landmarks.
The park’s collection spans vessels built between 1886 and 1914. Balclutha was built in 1886, Alma in 1891, Eureka in 1890, C.A. Thayer in 1895, Hercules in 1907, and Eppleton Hall in 1914. The six dates create a 28-year range across the collection, while the landmark designation identifies five vessels as especially significant within the National Park Service’s historic-vessel program.
Together, the ship counts, protected-area measurements, designation dates, and vessel construction years show several ways to measure maritime history. Wreck statistics record loss and discovery; sanctuary areas record the geography of protection; community figures record the human and economic setting; and preserved ships keep working vessels present as tangible historical evidence.