The Whaleback Shell Midden consists primarily of discarded sea animals' shells along with bones, ceramic pots, and some stone tools. The accumulations become deep and layered to great heights over thousands and thousands of years. The enormous shell heap of Whaleback can be found on the east side of the Damariscotta River. This midden was once much larger, but in 1880, a great deal of the shells were removed and processed into chicken feed.

Because the calcium carbonate in sea animals shells are alkaline, they reduce the acidity in the soil and thus items that would normal biodegrade over a matter of years, are preserved over a long period of time. This makes middens a great source of information about the years gone by.

Managed in cooperation with the Damariscotta River Association, the area around Whaleback Shell Midden is now a State Historic Site that includes a small hiking trail and fantastic views of the Damariscotta River. There is a series of interpretive panels that help to inform visitors about the history of the area.