Located on the South Shore of Long Island in the Town of Islip, the population of the CDP was 16,569 at the time of the 2020 census.

He built his home, the first in Sayville, in 1761, located at what is now the northwest corner of Foster Avenue and Edwards Street.

The townspeople held a meeting to decide on a name, and after Edwardsville and Greensville tied in a vote, one resident suggested "Seaville".

In the Bible, the word "sea" was spelled "s-a-y",[4][dubious – discuss][need quotation to verify] and "Sayville" became the name he sent to Washington.

Meadow Croft still stands and is part of Suffolk County's San Souci Lakes Nature Preserve.

In 1915 the transmitter allegedly relayed a message from the German embassy to "get Lucy", referring to the RMS Lusitania which was sunk on May 15.

[citation needed] Whether the signals coming from the transmitter in Sayville authorized the attack or not, they caused concern for the US government, which dispatched Marines to ensure that encrypted messages were not sent.

President Woodrow Wilson sent a contingent of Marines to seize the wireless station, making it the first hostile action taken by the United States against Germany during World War I.

From 1919 to 1932 Sayville was home to Father Divine, a controversial African American religious leader who claimed to be God.

At that time Sayville was predominantly a seasonal resort, and Father Divine's followers made good livings as native house sitters.

Excess traffic that Father Divine attracted made him unpopular even to businesses he patronized with large cash purchases.

Following a June 1932 trial and prison sentence for disturbing the peace, Father Divine moved to Harlem, New York, claiming that Sayville was racist.

On January 27, 1992, a 20 year old man was charged with arson following a fire that destroyed 19th century buildings on Main Street.

[9] In early March 2024, the Sayville United Methodist Church received criticism for one of its signs that contained the phrase, "Heaven has strict immigration laws.

[15] The Sayville train station is on the Montauk branch of the Long Island Rail Road and has connections to the ferries via taxi and van services.

They are a certified New York State Department of Health, Emergency Medical Service agency that provides Advanced Life Support (ALS) care.