As the United States of America spread further and further West, its writers gradually developed a more and more distinctive voice, one less noticeably influenced by Old World attitudes. It may be difficult for generations born during or after the Information Age to understand how physical proximity can influence ideas. But before a mouse click could transmit a news flash to Baltimore and Baghdad simultaneously, regional philosophies were dependent on how accessible the area was from outside.
The middle of the Kansas prairie in 1870, for example, was less cosmopolitan than Tribeca, New York because the overland journey requisite to reach the farmers in the middle of their wheat fields was prohibitive to large-scale interaction with the outside world, whereas a New Yorker could walk out his front door and immediately be confronted with newspaper headlines, conversation, and bookshops each pregnant with the latest intellectual trends.
This was particularly true of America (especially including Canada and Mexico) because of its size. Europeans have always been pretty snug, with the nearest big city never too far away, but America was a vast landscape with huge unpopulated areas. Sometimes the local inhabitants weren't very interested in what other people thought, content with plowing fields in peace, or gathering berries in peace, or stealing each others' horses in peace.
During the Colonial period there was little time or resources for any but essential writing. The Jamestown settlers, Pilgrims, and others faced hostile weather and (at times) hostile natives, and penning novels, poems and satire weren't high on their list of priorities. They did keep journals of their various ordeals, however, as well as government and church documents, sermons, and medicinal texts. When they weren't writing (which was most of the time), they were taming a new land, shooting turkeys, and going hungry.
More people came, and the land became more hospitable as it became more civilized, and gradually there was more time to write. Among the first novelists in the New World was Charles Brockden Brown, a complex writer whose work influenced generations after him. He embraced themes relating to the extent of human knowledge, the supernatural, and violence, reflecting both Enlightenment ideas and the fury of the Revolution from English sovereignty.
It took awhile for Americans to become themselves, comfortable in their own skins and in the land they claimed. The shadow of Europe was a long one, and it colored many of the greatest documents written on U.S. soil, specifically the Declaration of Independence, the U.S. Constitution, The Federalist Papers, and Benjamin Franklin's Autobiography. Only when they literally moved out of Europe's direct influence did American authors become distinctively American.
The United States republic was a political experiment of international proportions—the fact that it was a successful one influenced the American propensity for literary and philosophical experimentation. Herman Melville's Moby Dick remains a jarring and rewarding experience 160 years after its initial publication, and is a fine example of the developing willingness to disregard borders (metaphorically) and conventions (literally). Whitman's Leaves of Grass accomplished for the poem what Melville's masterwork did for the novel.
Sometimes a novel is born out of a confluence of cultural and geographical issues. John Steinbeck's The Grapes of Wrath was influenced by the rise of socialist idealism in the U.S., and by the Dust Bowl and Great Depression which resulted in forced migration for thousands of farm families originally from the Midwest. American literature is full of similar examples, all of them showing that no human creation is ever made in a vacuum or apart from the author's physical circumstances.
A few authors took this too far—coming into vogue in the late 19th century, they were called Regionalists because their output directly reflected the regions in which they lived. The problem with Regionalism is that it makes any universal elements present in the literature less accessible to those unfamiliar with the place under consideration.
Yet, to some extent at least, literature can only be understood if the factors of its creation are also understood. Who can really appreciate Lincoln's speeches or Frederick Douglass' memoirs who knows nothing about slavery or the American Civil War? Faulkner's entire body of work requires some idea (however vague) of the nature of the American South. The novels of James Fenimore Cooper are nonsensical minus the context of the early American frontier and the French and Indian Wars.
It's important to bear in mind that where a novel is written isn't everything. Postmodern deconstructionists like to assert that the author no longer exists—instead, any text is the result of various factors operating on the writer. This is clearly absurd. However, to suggest that a work comes entirely from within the author is equally absurd, and it's essential for understanding to be familiar with the place he or she comes from, even if only from a purely intellectual perspective.
The United States is a big place. Grouping books by "American Literature" is a fairly broad designation, but it's immediately helpful to know what country an author calls home before trying to decipher his body of work. Most of the major classics are here, and quite a few lesser-known offerings that are often just as compelling; if you look hard enough you're sure to find your own Independence Rock or Grand Canyon or Niagara Falls.