Give some stream of consciousness and then the answer. In the near future, fertility rates collapse as a result of sexually transmitted diseases and environmental pollution. With this chaos in place, the totalitarian, Christian theonomic government of "Gilead" establishes rule in the former United States in the aftermath of a civil war. Society is organized by power-hungry leaders along a new, militarized, hierarchical regime of fanaticism and newly created social classes, in which women are brutally subjugated, and by law are not allowed to work, own property, handle money, or read. Worldwide infertility has resulted in the conscription of the few remaining fertile women in Gilead, called handmaids, according to an "extremist interpretation" of a Biblical account. They are assigned to the homes of the ruling elite, where they must submit to ritualized rape with their male masters in order to become pregnant and bear children for those men and their wives.

Based on this passage, where does the handmaid's tale show take place?
To answer the question, consider the following: With this chaos in place, the totalitarian, Christian theonomic government of "Gilead" establishes rule in the former United States in the aftermath of a civil war.
Therefore, the answer is in the former United States in the aftermath of a civil war.