Southwestern United States, 1960
Like Norman Bates' psyche, Psycho's setting is divided in two.
First, there are the cities: Phoenix, Arizona and Fairvale, California. These are recognizable, everyday, daylight locations. Phoenix is a big city and Fairvale is a smaller town, but in both, people go to work, spend time with their families, and generally live normal, boring lives doing normal, boring things.
And then, outside the cities, there's something else. When Marion gets on the highway, she leaves normality behind. The road is dark and filled with ominous dangers—the policeman's mirrored sunglasses, the storm, and the eerily unoccupied Bates motel. To turn off of main street is to drive into madness and terror.
If you abandon your everyday routine, Psycho says, you will end, inevitably, buried in the swamp. Especially if you fund your road trip with someone else's cash.