You can plot Americans’ move westward.
“The mean centre of US population is “the point at which an imaginary, flat, weightless and rigid map of the US would balance perfectly if weights of identical value were placed on it so that each weight represented the location of one person on the date of the census”, in the definition of the US Census Bureau itself.”
See Also: From Strange Maps: The Sweet Tea Line In Virginia…Edward Hopper: Railroad Sunset