The U.S. Census Bureau and the National Oceanic and Atmospheric Administration have determined the exact center United States population.
Based on the 2020 U.S. census population of 331.4 million people, the center of population is just outside Hartville, Missouri, the U.S. Census Bureau announced. Located about 200 miles from St. Louis and about 90 miles from Branson in southern Missouri, Hartville is home to about 600 people.
The center of population represents the average location of where people in the United States live. It is the point where “an imaginary, flat, weightless, and rigid map of the United States would balance perfectly if everyone were of identical weight,” the Census Bureau explains.
A celebration was held earlier this week in Hartville to “show off the center of America.” In addition to speeches from City of Hartville, U.S. Census Bureau, and National Oceanic and Atmospheric Administration (NOAA) officials, there also were several musical performances.
NOAA even unveiled a permanent commemorative survey mark to designate the spot as the 2020 census center of population.
Determining The Precise Center Of Population
Ever since the first census in 1790, the Census Bureau has calculated the “center of population” every 10 years. What makes this challenging, however, is that Earth isn’t perfectly round and smooth.
“When you try to measure the distance from one place to another in a small area, you can mostly pretend it’s all made of flat surfaces,” Galen Scott from the National Geodetic Survey division of NOAA explains. “But for larger distances, you have to account for the curvature of the Earth, and that’s when it gets complicated.”
To do that, scientists use geodesy, which is the science of accurately measuring and understanding Earth’s geometric shape, its orientation in space, and its gravitational field.
“To measure points on the Earth’s surface, geodesists assign coordinates (similar to a unique address) to points all over the Earth. In the past, geodesists determined the coordinates of points by using Earth-based surveying tools to measure the distances between points,”
NOAA explains. “Today, geodesists use space-based tools like the Global Positioning System … to measure points on the Earth’s surface.”
Why It’s Important To Know The Center Of Population
In 1790, the first time the center of population was calculated, it was in Kent County, Maryland, about 20 miles east of Baltimore. Since then, the population center has steadily moved west as the nation has expanded.
For instance, the largest shifts in population were between 1850 and 1890, when people moved west due to the California Gold Rush and land speculation in Oklahoma. More recently, however, the center of population has moved to the southwest, due to trends in both immigration and people in the Northeast and Midwest moving to the Sun Belt, the Census Bureau explains.
Interestingly, towns in Missouri have been the center of population ever since 1980.
“The movement of the center of population helps tell the story of this century’s migration South and West,” Ron Jarmin, who was the Census Bureau’s acting director, said last fall. “It helps visualize where we live.”
In addition to calculating a national center of population, the Census Bureau also calculates centers of population for each state, county, census tract, and census block group.
What’s more, recording population numbers and how people move over time during a census helps government officials distribute congressional districts as well as planning for the allocation of government resources and infrastructure requirements.
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