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.
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.
In its migration, only twice has the center of population
come to rest in an actual population center: Baltimore, Maryland
(population center, 1800), and Covington, Kentucky (population
center, 1880, and hometown of a fourth-grade-dropout named
Haven Gillespie, who penned numerous classic American songs
including “Drifting and Dreaming” and “Santa Claus Is Coming
to Town”). Over the years, the centroid has been found in places
like Clarksburg, West Virginia, population center of 1840, where
today the FBI operates its National Instant Criminal Background
Check System to screen purchasers of firearms. Its path also
passes through Portsmouth, Ohio, childhood home of Roy Rogers, which held the distinction in 1870. Portsmouth lost its NFL
team to Detroit in 1933, its steel mills in the 1980s, and more
than half its population of forty thousand between 1950 and
2000. And let us not forget Olney, Illinois, which held the honor
in 1950. Hemmed in between industrial-scale farms, the town of
ninety-one hundred is perhaps best known for its population of
indigenous albino squirrels (penalty $500 for running one over),
whose habitat is restricted almost entirely to a single city park.
A great series of advances and contractions, the movement of
the American population has been di=use and complex, a mass
peopling counteracted by catastrophic bouts of depopulation. It’s
di;cult to imagine that a single measure could ever come close
to summarizing the process, let alone reduce it to a single, floating point. And yet, here you have it.
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.
For the next hundred years, the centroid moved steadily
westward, oscillating between the thirty-eighth and thirty-ninth
parallels, over the Appalachian highlands of West Virginia and
into the rolling pasturelands of southern Ohio and Indiana. As
the population fanned west, further weighting the lands on the
nation’s left half, the center was duly lured in its wake. Some
sought economic opportunity or self-reinvention in western cities. Some went in search of gold in the Sierra or silver in the
Rockies. Others were motivated by the promise of land and self-determination in giveaways such as the 1862 Homestead Act.
These new migrants were granted 160-acre parcels (later increased to 320 acres in the “enlarged” Homestead Act of 1909)
west of the Mississippi River. Many, however, found themselves
suddenly thrust into a life of toil and servitude to the land itself
as they clawed out a living from the arid and soon to be denuded
reaches of the Great Plains west of the hundredth meridian.
Between 1910 and 1930, the center did something it had
never done before or since. It remained virtually still. It’s not
that population ceased to grow or that it stopped expanding. But
the steady westward migration was counteracted by the mass immigration of millions of Europeans to the East Coast between
1890 and 1930, spurring draconian immigration laws such as
the National Origins Act.
By 1930, the center was on the move again. But instead of
continuing on its decisive westerly path it bent southward. That
deflection, a trend that has continued to the present, was touched
o= by the great Texas oil booms, the rise of manufacturing in
southern states, New Deal infrastructure projects including the
great water-storage and hydroelectric projects of the Tennessee
Valley Authority and Bureau of Reclamation, and the construction of permanent military bases in the South and West during
and after World War II.
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.
In the same period, Americans have abandoned the farm and
village for the urban tarmac and suburban lawn. Industrialized
agriculture and its attendant degradation of soils and depletion of