Ever since I saw the movie "In Dreams" (awesome scary movie with Annette Bening and Robert Downey Jr) with a scene of divers diving in a lake where a town was underneath, swimming amongst headstones and a church, I have been fascinated with the idea of abandoned sunken ghost towns.
Smith Island Chesapeake:
This island in the Chesapeake is lost to time. It is 3 miles long and 1 mile wide and at sea level. It's lost a good deal of its citizens to poor crabbing and fishing conditions. The graves are topped by heavy stones so when there's a high tide or flooding rains, the bodies don't wash away to sea. At the rate of shrinkage, the island will be gone by the end of this century.
Around the beginning of the 19th century, Sharps Island was a roughly 600-acre (240-hectare) farming and fishing community at the mouth of Maryland's Choptank River. At one time it boasted schools, a post office and a popular resort hotel, where vacationers from Baltimore and other locations would arrive by boat to while away the lazy summer days. But between 1850 and 1900, the island lost 80 percent of its land mass, and by 1960 it had been reduced to a shoal. Today it is entirely underwater, marked only by a partly submerged lighthouse.
Remember the movie "Deliverance?" Here's a dive to that town, Lake Jocassee, SC (go ahead and run the slider to closer to the end so you can see the dive if you don't want to hear the interview, but it is a nice story).
(Here's the cemetery on a dive...)
(Above: Loyston, TN, photographed before being sunk by a lake created from a dam)
Loyston (Wikipedia) was a community in Union County, Tennessee, USA, that was inundated by the waters of Norris Lake after the completion of Norris Dam in 1935. Established in the early 19th century around a foundry built by its namesake, John Loy, over subsequent decades the community's location along State Highway 61 helped it grow into a trading center for local farmers. By the time the Tennessee Valley Authority (TVA) began making plans to build Norris Dam in the early 1930s, Loyston had a population of approximately 70 residents, and consisted of a post office and several small businesses. Prior to inundation, TVA conducted extensive sociological surveys of Loyston's residents, and the community was documented by photographer Lewis Hine. Most of Loyston's residents relocated elsewhere in the area, with many forming the community of New Loyston in the hills to the south.