Riverside, known until 1870 as Mianus Neck, was a community known for fishing enterprises, orchards and farming. At that time, Riverside Avenue was called Potato Road because of the potato storage cellars near the cove. Legend tells us that the east bank of the Mianus River was named Dumpling Pond, for the colonial housewife during the Revolutionary War who threw her dumplings into the pond rather than having them taken by the British soldiers passing through after they destroyed the Lower Landing in Cos Cob. In 1870, the U.S. government approved a post office and the State of Connecticut changed the name of Mianus Neck to Riverside.
The Riverside Yacht Club, founded in 1888 was a strength which drew people from New York City and other parts of the country to settle into homes in Riverside. The shore of the Long Island Sound was extremely attractive to the wealthy in pursuit of property to build estates.
To maintain a strictly residential section of town, The Riverside Association was formed in the late 1920's. The Association was successful in shutting down several stores but they were unable to shut down the variety shop, Ada's, because it had pre-existing rights. Today, Ada's is a community landmark originally known for its penny candies. It is one of the only commercial entities in Riverside south of the Post Road.
Since the early 1900's Riverside has always been a community lacking ostentation. Its population consists of executives, plumbers, shop owners and employees of all levels, living together as neighbors. Riverside children originally attended school in Old Greenwich. In the 1930's the Old Greenwich School became extremely overcrowded. In 1933 Riverside got its own elementary school and in 1955 Eastern Junior High School was built across the street. Riverside continued to grow and develop and is now a sought-after and close-knit residential community.