American fiction is any type of published fictional story produced by an American author, or by an author from another country writing about America or the idea of being American. This is a fairly broad definition, which means the different genres of American fiction will be wide-ranging as well. An American writer can, for example, write science fiction and fantasy, horror, literary fiction, general fiction, family saga, Westerns, historical fiction, and so on. These stories can take the form of novels, novellas, short stories, and flash fiction.
The genre that is perhaps best known as American fiction is the Western. Westerns focus on the early settlement years of the Western states of the United States, and they usually revolve around stories of cowboys, settlers, farmers, ranchers, Native Americans, and so on. Many westerns feature themes of morality or immorality, battles of good versus evil, and the struggle to survive in harsh landscapes such as the Plains States and the deserts of the Southwest. This genre of American fiction is so ingrained in themes commonly associated with America and being American because many of the prominent writers of western fiction were alive to witness the expansion and development of the nation firsthand. Westerns still live on in fiction, though much of the Wild West realities have gone by the wayside.
The category of writing known as American fiction is a relatively new category that is only as old as the nation itself, or slightly older. Genres that have developed over the course of the nation's history include horror, fantasy, and science fiction, all of which may have developed as a continuation of fiction from other countries. Horror stories present themes intended to frighten readers, while science fiction often focuses on futuristic themes, technology, and human development. Fantasy can take place in fictional worlds far different from reality, and the themes can therefore venture into the highly hypothetical.
General fiction is any story that does not fall into a specific genre, but instead focuses on everyday stories and characters, common themes, and relatable struggles. The term "literary fiction" is often reserved for these books and others that focus on high quality writing, new and revolutionary prose styles and themes, and so on. General fiction and literary fiction are most often likely to intersect, more so than other genres. Horror and science fiction are likely to intersect, as are horror and fantasy, or science fiction and fantasy.