GREAT DIVIDE • FREE-TRANSLATOR.COM • Definition of Great Divide

... western drift of our people began almost at the moment when they became Americans, and ceased to be merely British colonists. They crossed the great divide which sundered the springs of the seaboard rivers from the sources of the western waters about the time that American citizens first publicly acted as American freemen, knit together by common ties, and with interests no longer akin to those of the mother country. ...

— The Winning of the West, Volume One - From the Alleghanies to the Mississippi, 1769-1776 • Theodore Roosevelt