 The town of Greenwich is one political and taxing body, but consists of several distinct sections or neighborhoods, such as Byram, Cos Cob, Glenville, Mianus, Old Greenwich, Riverside and Greenwich (sometimes referred to as central, or downtown, Greenwich).Of these neighborhoods, three (Cos Cob, Old Greenwich, and Riverside) have separate postal names and ZIP codes.One of the founding settlers of Old Greenwich was Elizabeth Fones, niece and daughter-in-law of John Winthrop, founder and Governor of the Massachusetts Bay Colony.