The Central United States is sometimes conceived as between the Eastern United States and Western United States as part of a three-region model, roughly coincident with the Midwestern United States plus the western and central portions of the Southern United States; the term is also sometimes used more or less as a synonym for the Midwest, omitting all or most of the South. 4 of 9 Census Bureau Divisions have names containing "Central", though they are not grouped as a region. They include 20 states and 39.45% of the US population as of July 1, 2007. * * * Continental divides in North America.