The Centroid | Orion Magazine: SINCE THE FIRST DECENNIAL CENSUS in 1790, the center of population has moved roughly 870 miles southwest, from a point near Baltimore to a tiny hamlet in central Missouri at the fringe of the Mark Twain National Forest. The movement of the center is driven by regional population growth. It’s pushed and pulled by a kind of urban magnetism: the larger the population of a city or town, the greater the tug.
To trace the path of the centroid is to skim a great narrative spanning 220 years. That narrative is the nation’s history of growth, with each point along the way emerging as a sort of chapter: the rise of industrialism in the Northeast, the expansion of the western frontier, the waves of European, Latin American, and Asian immigration, the post–World War II population boom.