The story is primarily set in the Salinas Valley, California, between the beginning of the twentieth century and the end of World War I, though some chapters are set in Connecticut and Massachusetts, and the story goes as far back as the American Civil War.
In the beginning of East of Eden, before introducing his characters, Steinbeck carefully establishes the setting with a description of the Salinas Valley in Central California.
Then he outlines the story of the warmhearted inventor and farmer Samuel Hamilton and his wife Liza, immigrants from Ireland. He describes how they raise their nine children on a rough, infertile piece of land. As the Hamilton children begin to grow up and leave the nest, a wealthy stranger, Adam Trask, purchases the best ranch in the Valley.