One historian wrote that the seeds of the American Civil War were planted in the settlements of Jamestown and Plymouth, two and a half centuries earlier. (It might be worthwhile for you to look up that quote...)  From the very beginning of English colonization in North America, two different sets of colonists, with different ideologies, religious conviction, social standing, and educational convictions established different colonies, and these, from the very start, separated along the geographical North and South.  The economies of both areas were different, and over time manifested Northern industry and Southern agriculture.  Even founding the United States in 1776 brought these two divergent areas in conflict (If you haven't already, see the musical "1776" which shows how close the US came to not declaring independence from Britain because of political divisions between North and South) and was only partially resolved by compromise.  Throughout the 19th century, this pattern of compromise maintained the US as a single country; when compromise finally failed in the 1860's war was the inevitable result.