is a hamlet located in the town of New Castle, New York in Westchester County. It was originally settled as Sarlesville. The area now known as Millwood appears on 19th century maps as Merritt's Corners (now the intersection of Rtes. 100 and 120) and Rockdale Mills (close to what is now the Briarcliff Manor border). As of the 2000 census, the community had a population of 1,210.