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.
In 1790, the first decennial census plotted the center of population in Kent County, Maryland, some twenty-three miles east of Baltimore. It was just two years after the ratification of the Constitution, and the U.S. population was concentrated along the Eastern Seaboard in the port cities of Boston, New York, Baltimore, and Charleston. New York, with a population of a little more than thirty-three thousand, was the nation’s largest city—and has remained so ever since. It’s hard to imagine, however, that Marblehead—today a quaint and touristic village a half-hour north of Boston—was then the nation’s tenth largest city, with a population of just under six thousand.And here is a comment with which I completely agree and yet it does not get enough attention:
But arguably, the most influential factor in this change of course is air conditioning. That the centroid is headed, of all directions, southward, is a testament to our ability to blithely overpower climate with the brute force of fossil fuel. According to the 2010 Census, the Sunbelt cities of Los Angeles, Houston, Phoenix, San Diego, San Antonio, and Dallas now comprise six of the country’s ten largest cities. Over the last decade, the population of southern states has increased by around 14 percent, the fastest growth of any region in the country, outpacing the national growth rate of nearly 10 percent.But, on the other hand, he slipped a bit with this comment:
Today there are an estimated 11 million undocumented (which is to say, uncounted) immigrants scattered across the country. Any talk of the centroid or its “advance” must be considered in light of these unaccounted-for populations.While some of these people probably were not counted, in general we estimate the number of undocumented immigrants by comparing counts of foreign-born persons in the census and other Census Bureau surveys, such as the Current Population Survey and the American Community Survey, with the counts of authorized immigrants from those countries. The difference is assumed to represent the undocumented population. They are undocumented, but they are also counted.