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,[5] niece and daughter-in-law of John Winthrop, founder and governor of the Massachusetts Bay Colony.

During "off season", Innis Arden, a local golf club, is a popular sledding destination for kids in Old Greenwich and neighboring Stamford.

Condé Nast operated a printing facility in Old Greenwich from 1924 to 1964 that published many different magazines, including Vogue, Vanity Fair, and House & Garden.

The original "well-to-do" population lived mainly in "the Back Country" (north of the Merritt Parkway) or in the exclusive Belle Haven area on the waterfront.