Eastham () is a town in Barnstable County, Massachusetts, United States, Barnstable County being coextensive with Cape Cod. The population was 4,956 at the 2010 census.
For geographic and demographic information about the village of North Eastham, please see North Eastham, Massachusetts.
Originally settled by the Nauset tribe, Eastham was the site where in 1620 a hunting expedition landed, comprised from the crew of the sailing vessel Mayflower, which had stopped in Provincetown harbor on Cape Cod Bay after a rough crossing of the Atlantic Ocean, which led to the first encounter of the Pilgrims and the local Nauset people at First Encounter Beach. The area would not be settled by Europeans, however, until 1644. The original lands included what are now the towns of Truro, Wellfleet, Eastham, Orleans and a small portion of Chatham. Eastham town was officially incorporated in 1651.
Eastham is the birthplace of Freeman Hatch, who in 1853 set the world record for a single-hull wooden sailing vessel from San Francisco around Cape Horn to Boston aboard the clipper ship Northern Light. Fishing and especially farming were early industries in the town, and writers and artists also came to the town. Gustavus Franklin Swift, born in Sagamore, MA, began his first meatpacking business in Eastham which later moved to Brighton, MA, Albany, NY, and eventually started the meatpacking industry in Chicago. It was in Eastham that Henry Beston wrote The Outermost House. The town is discussed at some length in Henry David Thoreau's Cape Cod as the somewhat rugged site of one of New England's largest summer "camp-meeting" evangelistic gatherings in the mid-19th century.