Some maps dating as early as 1632 identify the water off Bayside as Garretson's Bay or Matagarreton's Bay and was, in all likelihood, named after Mathew Garretson, a Dutch settler who founded a small colony in the area.

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Although the Dutch Governor of New Amsterdam, William Kieft, granted land to 18 patentees in 1645 Garretson was not one of them. There is very little information about Bayside from this period as a fire in the town clerk's home of Jeremiah Vanderbilt in 1789 (where the records were kept) destroyed much of the documents. The story has it that a 17-year-old slave set the fire because Vanderbilt would not let her marry. The arsonist blamed for the fire was arrested and New York State Attorney General Aaron Burr (1756-1836) put the suspect on trial. She was ultimately convicted and hanged.

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Alternatively, the Matinecock Indians called the bay Menhaden-Ock, translating as "place of fish." White settlers mangled the pronunciation of Menhaden-Ock and it evolved into Madnan's Neck and then ultimately to Little Neck.