is a hamlet (and a census-designated place) located within the Town of Oyster Bay in Nassau County, New York. As of the United States 2000 Census, the CDP population was 3,521.
The rolling hills of the North Shore of Long Island were laid down as terminal moraines by the receding glaciers of the last ice age roughly 10,000 years ago. The Algonquin tribe that settled the area, spanning from Flushing to Setauket, called the area "hilly ground" or Matinecock and as a result the Algonquin Indians who settled there became known as the Matinecock Indians.
In 1667, Captain John Underhill negotiated with the Matinecock Indians to purchase land for a settlement that he and his fellow colonists would call Buckram. The town name lasted for nearly 200 years, when in 1856 the name was changed to Locust Valley based on the number of locust trees located in the area. On April 19th 1869, the Long Island Rail Road opened the extension of the Glen Cove line, via a single track to Locust Valley, making it the terminus of the line until the railroad was extended to its current terminus in Oyster Bay in 1889.
With the arrival of the Long Island Rail Road, a commercial center developed and thrived around the station and the nearby intersection of Forest Ave/Buckram Road and Birch Hill Road. As the North Shore of Long Island grew into the Gold Coast in the early 20th century, the commercial center grew to serve great estates that were being established in the surrounding communities of Lattingtown, Mill Neck, Matinecock and Brookville. As the commercial center and with the railroad station for the surrounding Gold Coast communities, Locust Valley, though geographically small, became the name of reference for the surrounding areas between Glen Cove and Oyster Bay.
As Locust Valley's name became synonymous with the surrounding communities, it was associated with the upper-class accent prevalent on the great estates: "Locust Valley Lockjaw". While the accent is not heard as much as it once was, Locust Valley remains a social center for upper-class New Yorkers. Many are members of the exclusive country clubs in the area: Piping Rock and the Creek.