The American frontier comprises the geography, history, folklore, and cultural expression of life in the forward wave of American westward expansion that began with English colonial settlements in the early 17th century and ended with the admission of the last mainland territories as states in 1912. In North American development, "frontier" refers to a contrasting region at the edge of a European-American line of settlement, or settled area. American folklore is focused primarily on the 19th century, especially west of the Mississippi River. Enormous popular attention in the media focuses on the Western United States in the second half of the 19th century, a period sometimes called the Old West, or the Wild West, frequently exaggerating the romance and violence of the period.