Underwater archaeology is a subfield of archaeology that focuses on the exploration of submerged archaeological sites in seas, rivers, and other bodies of water. In 1988, the Maryland Maritime Archeology Program (MMAP) was established with the goal to manage and explore the various underwater archaeological sites that line the Chesapeake Bay. This was in response to the National Abandoned Shipwreck Act passed in 1987, which gave ownership of historically significant shipwrecks to those states with proper management programs.
Water makes up 25% of the State of Maryland and there are over 550 submerged archaeological sites that have been located across the Chesapeake Bay and its surrounding watersheds. Ranging from 12,000-year-old, precolonial native settlements to shipwrecks from as recent as World War II, the MMAP researches thousands of years worth of history in these archaeological sites. Susan Langley has been Marylands State Underwater Archaeologist, one of only nine state-appointed underwater archaeologists in the United States, since assuming the role in 1995. Before Langley was hired, only 1% of the underwater archaeological sites in the bay area had been examined. Over the next 10 years, Langley made significant improvements to the MMAP's marine technology, allowing her and her team to explore 34% of the underwater archaeological sites by 2004.