Caumsett State Historic Park Preserve is on Lloyd Neck, a peninsula extending into Long Island Sound in the village of Lloyd Harbor, Long Island, New York.
In 1654, the Matinecock Native Americans sold 3,000 acres (12 km2) of what is now called Lloyd Neck to English settlers from Oyster Bay on Long Island. The Matinecock referred to the region as Caumsett (place by sharp rock).
In 1676, James Lloyd acquired the neck, which was then taken over by his son Henry. Henry Lloyd farmed the land and erected a house, which still survives in Caumsett State Park.
After his death in 1763, his son, Joseph, built the Joseph Lloyd Manor House, which he was forced to abandon by the British during the Revolutionary War.
The British built several fortifications in the neck, including Fort Franklin. Henry Lloyd IV was the last Lloyd to own the estate in 1841.
In the 1880s, it became a stop for steamboats coming from New York City bringing tourists and wealthy New Yorkers.
The 1900s ushered the era of the Long Island Gold Coast and various wealthy families began to buy land and build seaside mansions and estates. These included William Matheson, Marshall Field III, Ronald Conklin, Harold Dimppel, Sr., Ferdinand Eberstadt and George McKesson.
Currently, many of these estates have been adapted for other uses. Marshall Field III's estate is now Caumsett State Historic Park, and the Conklin estate is a Roman Catholic seminary. Others have become a county park and a wildlife refuge.
Marshall Field III (September 28, 1893 – November 8, 1956) was an American investment banker, publisher, racehorse owner/breeder, philanthropist, heir to the Marshall Field department store fortune and a leading financial supporter and founding board member of Saul Alinsky's community organizing network Industrial Areas Foundation.