The Incorporated Village of Muttontown is a village located within the Town of Oyster Bay in Nassau County, New York, United States. The population was 3,497 at the 2010 census. Muttontown was ranked one of the wealthiest towns in America by BusinessWeek. The village and surrounding areas, which make up the "Gold Coast" of Long Island, have historically been home to some of the most affluent families in New York. The name of the village stems from its former use as pasturage for sheep.
The following copied from info provided by Walter Greenspan and found at the Nassau County rootsweb archives: When Muttontown incorporated and became a village (Municipal corporation) in 1931, it took some of its land from what may have been then a slightly larger Hamlet of Locust Grove. The Village of Muttontown, as did the Hamlet of Locust Grove, did not and does not have a same-named post office, and thus no place in the Village of Muttontown has a "Muttontown, NY" mailing address. Depending where a place in the Village of Muttontown is located, that place can have either: a "Jericho, NY" , a Syosset, NY", a "Glen Head, NY", an "East Norwich, NY" or an "Oyster Bay, NY" mailing address.
Prior to 1990, Locust Grove was a hamlet in the central part of the Town of Oyster Bay, Nassau County. There was no "Locust Grove, NY" post office, and thus no place in the Hamlet of Locust Grove had a "Locust Grove, NY" mailing address. The majority of places in the Hamlet of Locust Grove had a "Syosset, NY" mailing address, while some places in the Hamlet of Locust Grove had a "Jericho, NY" mailing address.
In 1990, the Hamlet of Locust Grove was absorbed into the Hamlet of Syosset and now forms all that part of the Hamlet of Syosset south of the Jericho Turnpike.