The story doesn't take place in only one location. In the present time, the story takes place where Hannah lives, in New Rochelle, NY and when she travels to the Bronx in NYC for Seder. However, in the story she is taken back in time to Poland, and then ends up in a Nazi concentration camp.
This is a book that you should definitely read -- and not just find the answers to questions. None of us can be truly part of the human experience unless we have a real connection with the suffering our kind have caused.
Jane Yolen's The Devil's Arithmetic deals with the historical impact of the Holocaust within a modern setting. Initially, this story begins in present day New Rochelle, New York. It strikes me as a middle class or affluent suburb of New York. A modern family, driving a modern car, travel to a family gathering. While no exact year is given, it is contemporary as seen through Hannah, who is concerned with adolescent concerns of popularity, social acceptance, and being more like her friends. This feeds her resentment of her familial and cultural traditions, one of which is the focus of the start of the novel.