The differences between East Egg and West Egg are mostly implied in the novel, but several passages speak directly to their conflicting atmospheres and social standings. Early in Chapter I, Nick mentions West Egg for the first time. He says, "It was a matter of chance that I should have rented a house in one of the strangest communities in North America." Immediately, West Egg is identified as being far from a traditional place to live. Nick then describes the physical shape and appearance of the Eggs as they would be observed from the air; from above, they look quite similar. In fact, Nick tells us, "a more arresting phenomenon is their dissimilarity in every particular except shape and size." Now we know that West Egg is not only strange, it is different from East Egg in every way except its physical topography.
Continuing in this passage from Chapter I, Nick says that West Egg (where he lived) was "the less fashionable of the two." He then comments that "less fashionable" is inadequate in explaining the "bizarre" and "sinister" difference between them. These references foreshadow events to come.
A brief but significant reference to the contrast between East Egg and West Egg occurs in Chapter III at Gatsby's party. Guests from East Egg stay in their small group, choosing not to associate with people who are different from themselves. Their attitude of superiority is clear:
Instead of rambling this party had preserved a dignified homogeneity, and assumed to itself the function of representing the staid nobility of the countryside--East Egg condescending to West Egg, and carefully on guard against its spectroscopic gayety.
Through Nick's observations, Fitzgerald establishes early in the novel a distinct conflict between the societies of East Egg and West Egg.