town (township), Westchester county, southeastern New York, U.S., between Yonkers to the west and New Rochelle to the east. Its first settlers issued their own code of laws called the Eastchester Covenant (1665). Eastchester township was organized in 1788 and derived its name from Chester, England; at one time it extended from Scarsdale to Goose Island in the Bronx. The township includes the unincorporated village of Eastchester and the villages of Bronxville (incorporated 1898) and Tuckahoe (1903). Area 5 square miles (13 square km). Pop. (1990) 30,867; (2000) 31,318.