Long island was an island located in the state of New York in the United States of America on Earth.
In Dangerous Games, Hendler's Sanitarium was located on this island. (TNG: "The Big Goodbye")
The pages seen in the episode were from the mystery novel,
Dangerous Ground, by author Frances Sil Wickware. This novel was published in 1946. Information on Long Island was from page 13.
In 2009, Denise C. Raymond, the daughter of Edward Raymond and Ginger Summers, was born on this island. (TNG: "The Neutral Zone")