Map - Oyster Bay (hamlet), New York (Oyster Bay)

Oyster Bay is a hamlet and census-designated place (CDP) on the North Shore of Long Island in Nassau County in the state of New York, United States. The hamlet is also the site of a station on the Oyster Bay Branch of the Long Island Rail Road and the eastern termination point of that branch of the railroad.

The community is within the Town of Oyster Bay, New York, a town which contains 18 villages and 18 hamlets.

The hamlet's area was considerably larger before several of its parts incorporated as separate villages. At least six of the 36 villages and hamlets of the Town of Oyster Bay have shores on Oyster Bay Harbor and its inlets, and many of these were previously considered part of the hamlet of Oyster Bay; three of those are now known as Mill Neck, Bayville & Centre Island. The Oyster Bay Post Office (ZIP code 11771) serves portions of the surrounding villages also, including Oyster Bay Cove, Laurel Hollow, Mill Neck, Muttontown, Centre Island, Cove Neck, and Upper Brookville.

The Oyster Bay-East Norwich Central School District was created on July 1, 1960, by the action of the voters in the former Oyster Bay and East Norwich School Districts. The district's 13.1 sqmi boundaries include the hamlets of Oyster Bay and East Norwich and the incorporated villages of Centre Island, Oyster Bay Cove, Cove Neck, and portions of Mill Neck, Muttontown, Laurel Hollow, and Upper Brookville. There are three schools currently in the district: Roosevelt Elementary School (Grades K-2), James H. Vernon Middle School (Grades 3–6), and Oyster Bay High School (Grades 7–12).

The population of the CDP of Oyster Bay as of the 2010 Census was at 6,707.

The first mention of Oyster Bay comes from Dutch Captain David Peterson de Vries, who in his journal recalls how on June 4, 1639, he "came to anchor in Oyster Bay, which is a large bay which lies on the north side of the Great Island… There are fine oysters here, whence our nation has given it the name of Oyster Bay."

Oyster Bay was settled by the Dutch, and was the boundary between the Dutch New Amsterdam colony and the English New England colonies. The English, under Peter Wright, first settled in the area in 1653. The boundary between the Dutch and English was somewhat fluid which led to each group having their own Main Street. Many Quakers came to Oyster Bay, escaping persecution from Dutch authorities in New Amsterdam. These included Elizabeth Feake and her husband Captain John Underhill, whom she converted to Quakerism.

Other notable Quakers to settle in Oyster Bay were the brothers John Townsend and Henry Townsend. Noted dissenter and founder of Quakerism George Fox visited Oyster Bay in 1672, where he spoke with the Wrights, Underhill and Feake at a Quaker gathering on the site of Council Rock, facing the Mill Pond.

During the Revolutionary War, Raynham Hall was owned by the irredentist Townsend family. For a six-month period from 1778 to 1779, the Townsend home served as British headquarters for the Queen's Rangers led by Lt. Col. John Graves Simcoe. Simcoe was often visited by British officer Major John Andre. According to legend, on one of these visits Samuel Townsend's daughter Sally Townsend overheard the two officers discussing Benedict Arnold's traitorous plot to surrender the fort at West Point to the British. The plot was thwarted when three Americans on patrol captured Andre near West Point, preventing what would have been a disastrous defeat for the colonists in the Revolutionary War.

In the 1880s, the Long Island Rail Road (LIRR) extended rail service from Locust Valley as a means to establish a connection between New York and Boston, via steamboat on Long Island Sound. On June 21, 1889, the first LIRR train arrived in Oyster Bay. In the following year, service commenced with the train coaches being loaded onto a ferry for a connection to the New Haven Railroad at Norwalk, CT. Service lasted less than a year.