The novella is predominantly set at a fictional country estate called Bly, which is situated in Essex, England. The frame narrative, however, begins in a home outside of London on Christmas Eve and presumably takes place at some point in the late 1800s, which is when The Turn of the Screw was written.
Having established the frame device (in which a group of friends are sitting around a fire telling ghost stories), the novella jumps back to the 1840s, which is when the governess went to work and live at Bly. The rest of the tale takes place at Bly. This remote setting is an important element because it makes the governess feel shut off from outside influence, effectively isolating her in an ominous and mysterious environment. What's more, her employer's insistence that she should never contact him isolates her even further—so much so, in fact, that she refuses to write to him when things start to go wrong at Bly. At first, her refusal to write to her employer just seems like a desire to follow his rules and do her job satisfactorily. By the end, though, her judgment has been called into question by the fact that nobody else seems to see the ghosts that she claims are trying to torment the children, and her overly protective nature toward Flora and Miles comes to seem somewhat sinister, inviting readers to wonder if her refusal to seek outside help has actually just been part of her delusional obsession with protecting the children. The fact that this all plays out against a backdrop of rural isolation only adds to the unsettling possibility that the children aren't quite as safe with the governess as it first seemed. To that end, Bly is clearly a dangerous place for the children no matter how one looks at the situation: they're either stranded in this secluded location with a disturbed caretaker or with malicious ghosts.
