There are three main settings: East Egg and West Egg that form Long Island and Valley of Ashes. Each part of the setting is represented by certain characters.
The description of the setting starts with “Twenty miles from the city a pair of enormous eggs, identical in contour and separated only by a courtesy bay, jut out into the most domesticated body of salt water in the Western hemisphere, the great wet barnyard of Long Island Sound.”
Our narrator Nick Carraway lives at West Egg “the less fashionable of the two”. Nick lives here because he doesn’t earn much
money to live on the other side. He lives “at the very tip of the egg…and squeezed between two huge places that rented for twelve or fifteen thousand a season”. This very description gives the reader a sense that Nick doesn’t belong to this side of the Egg. But somehow he is here. Here also lives Gatsby, the main character of the book after whom the novel is named. “The one on my right… - it was a factual imitation of some Hotel de Ville in Normandy…It was Gatsby’s mansion”. People here are wealthy and showy, they like pleasure and parties “an evening was hurried from phase to phase towards its close”. And everything here represents the roaring twenties. People are gathered from different layers. All of them have earned the money themselves. They aren’t elite but the one who want to become one.
“Across the courtesy bay the white palaces of fashionable East Egg”. This side is more expensive and it is represented by the Buchananas. People here form elite of American society “their house was even more elaborate than I expected, a cheerful red-and-white Georgian Colonial mansion, overlooking the bay.” This young family couldn’t have possibly earned the money themselves. They’ve just inherited the wealth from their parents. They don’t have any plans, they live for their pleasure.
These two Eggs are opposed to each other. West Egg doesn’t like people who live in East, maybe because they are envy. East Egg hates West Egg because of all those rich newcomers.
Valley of Ashes is situated “about half way between West Egg and New York”, which “is bounded on one side by a small foul river”. It is opposed to both sides of Eggs. The Wilsons live here. It is a grey and dirty place. People live here in poverty.
There’s a sharp border between all these three settings. The tragedy of the novel takes place in Valley of Ashes and at West Egg. The paradox is that it is caused by the careless Buchanans the representatives of East.
In conclusion, the geographical location gives us an idea of each person, their background and helps us to make a connection between them.