This article is from Malcolm Gladwell (Blink, Talking to Strangers, others) on the 60 or 70 thrillers he reads annually. He divides them into four genres.
“A Western takes place in “a world in which there is no law and order, and a man shows up and imposes, personally, law and order on the territory, the community.” An Eastern is “a story where there is law and order, so there are institutions of justice, but they have been subverted by people from within.” In a Northern, “law and order exists, and law and order is morally righteous, the system works.” (A prime example is, of course, Law and Order.) A Southern is “where the entire apparatus is corrupt, and where the reformer is not an insider but an outsider.”
There’s more of course. Read about it here