While the novel never gives us the exact year, we know that the novel is set in Jamaica at some point after 1834. (By the end of Part I, Antoinette mentions that she enters the convent in 1839 [I.2.4.1].) While in Jane Eyre the events take place in the 1800s, Rhys moves the events up thirty years during a time of social and political upheaval in Jamaica, which is at the time a British colony.
The novel opens a few years after Britain passed the Emancipation Act of 1833, which went into effect a year later (fifteen years before the French, and nearly thirty years before the Americans, we should add). While slaveholders were promised compensation for freeing their slaves, many slaveholders, like Antoinette's father, Mr. Cosway, and her neighbor, Mr. Luttrell, never received payment and were ruined. The newly freed slaves, on the other hand, are stuck in an apprenticeship system for four years following the act which is just as bad as slavery: they're forced to apprentice for their former owners, and the punishment for escaping was just as bad as the punishment under slavery. Not surprisingly, the former slaves continue to bear a major grudge against their former owners, and riots are common. Because so many plantations go under, many English investors arrive at the island seeking a good deal – people like the Luttrells and Mr. Mason, and, indirectly, Rochester. It's tough to pity the former slaveholders, we know, and one important question is whether you feel that Rhys's novel seems at all nostalgic for that period in Jamaican history.
In Part II, the novel moves to Granbois, the Cosway estate outside Massacre, Dominica. Unlike Jamaica, Dominica has flip-flopped between British and French imperial control over the years. At the time, it is also known as a stronghold of the Caribs, an indigenous Caribbean people. In the past, the Caribs have periodically staged insurgencies against the British and the French. The name of the town "Massacre" refers to a particularly bloody massacre of the Caribs, but nobody who lives there remembers the massacre itself. It's just another creepy name, as far as they're concerned. (Learn more.) The name "Granbois," meaning "big tree" or "big wood," underscores the creepiness of the locale. There's nothing wrong with big trees in general, but in the novel, big trees echo the dark forests of Antoinette's nightmares.
The novel ends in Thornfield Hall, England, Rochester's home. Unlike Parts I and II, where we get lush descriptions of the Caribbean, we don't see much of England since most of it is from Antoinette's point of view, who's locked up in the attic. It's no wonder that she thinks she's stuck in a world made of cardboard, and not in England. Her belief that she's living in a world made of paper is a not-so-subtle hint that the novel has returned to the primary landscape of Jane Eyre, the Victorian novel which it freely adapts.