is a hamlet and census-designated place in northern Westchester County, New York. As of the 2000 census, the population was 11,009. Chappaqua is located in the Town of New Castle.
In the early 1730s a group of Quakers moved north from Purchase, New York, to settle in present-day Chappaqua. They built their homes on Quaker Street and held their meetings at the home of Abel Weeks. Their meeting house was built in 1753 and still holds weekly meetings each Sunday. Horace Greeley's home still stands in Chappaqua.
Various spellings were used for the name they heard Native Americans use for their valley and hillside. It was an Algonquian word, "shah-pah-ka," and it meant "the rustling land" or "the rattling land," or a place where nothing is heard but the rustling of the wind in the leaves. The quakers spelled it Shapiqua, Shapaqua, Shapequa, Shappaqua, and, finally, Chappaqua. Their meeting was often referred to as the Shapequa Meeting as early as 1745.