There are two primary settings that impact the development Jackson's "The Possibility of Evil." One of these setting is the small town where the story takes place. It is universal in scope, never being identified by specific name. This setting of the town impacts the story in a couple of ways. The first is that it helps to establish the world in which Mrs. Strangeworth lives. It is a world that she has lived in all her life. As the town looked "washed and bright," it is clear that her identity is linked to the town, as "she had never spent more than a day outside this town in all her long life." The town is what enables the dramatic narrative to take place. As Mrs. Strangeworth walks about the town, the people she meets become the subject of her notes. It is the town's setting that helps to drive her desire to eliminate the "possibility of evil" through notifying people of the elements that she deems sinister in their worlds. In this way, the setting of the town impacts the story. The people she meets in the town, in the form of her desire to challenge the vision of evil in the world around her represent her primary motivation:
The town where she lived had to be kept clean and sweet, but people everywhere were lustful and evil and degraded, and needed to be watched; the world was so large, and there was only one Strangeworth left in it.
It is in this manner where the town as a setting helps to impact the story.
The other setting that impacts the plot is Mrs. Strangeworth's home itself. This is where Mrs. Strangeworth cultivates her roses, elements that are precious to her identity and sense of self in the world. It is also where Mrs. Strangeworth cultivates her second pride, her ability to write the letters that are the means through which she confronts the perceived evil in the world, in the form of the letters. Jackson describes the world of Mrs. Strangeworth's home as its own essential setting:
The perfume of roses meant home, and home meant the Strangeworth House on Pleasant Street. Miss Strangeworth stopped at her own front gate, as she always did, and looked with deep pleasure at her house, with the red and pink and white roses massed along the narrow lawn, and the rambler going up along the porch; and the neat, unbelievably trim lines of the house itself, with its slimness and its washed white look….
Jackson makes Mrs. Strangeworth's home as having a significant impact on the setting. It is a reminder of the "washed" manner in which Mrs. Strangeworth approaches evil and is also the immediate world where she defends her other "prized possession" of the town, itself. The world of Main Street, where she encounters the different citizens in the town, and her home are settings that define her actions. Through the interactions in one, she manifests their reality in the other. The letters that are composed about the town are done so in her home, at her "narrow desk," and with her stationery for the letters. It is here in which both the town and her home are critical settings to the story.
Both settings represents the individual's desire to appropriate reality in accordance to their own subjectivity. The internal frame of reference that Mrs. Strangeworth possesses is possible only through the small town and her home, both elements that define the story's trajectory. Jackson develops both settings as reflective of the mind of Mrs. Strangeworth. It is a consciousness that cannot fathom the perceived presence of evil and cruelty that has come to infect both by the end of the story. Both the town and her home help to develop the limits of evil and the extent to which its reach is felt in the modern individual.