Newcastle is a town in Lincoln County, Maine, United States. The population was 1,748 at the 2000 census. The village of Newcastle is located in the western part of the town, on the Damariscotta River. Together with the village of Damariscotta linked by the Main Street bridge, they form the Twin Villages (see Damariscotta-Newcastle CDP).
Originally called Sheepscot Plantation, it was first settled in the 1630s by fishermen and around 50 families. John Mason purchased a considerable tract of land about 1649-1650 from the sachems Chief Robinhood and Chief Jack Pudding. The territory was claimed in 1665 by the Duke of York. Renamed New Dartmouth, the plantation was attacked and destroyed in 1676 during King Philip's War. When the war was over, some of the inhabitants returned. But it was destroyed again in 1689 during King William's War, and the village was not reoccupied for about 40 years. In 1730, Colonel David Dunbar, the superintendent and governor of the Province of Sagadahoc, resettled it as Newcastle, named in honor of the Duke of Newcastle.
In 1978, the picturesque village of Sheepscot on the Sheepscot River in western Newcastle was listed on the National Register of Historic Places as the Sheepscot Historic District. It includes 51 buildings in the Italianate, Greek Revival, and Federal styles, on 12,000 acres (49 km²). (The USGS recognizes Sheepscott, Shepscooke, Shippscutt, and Shipscot as variants of the name Sheepscot.)