The Census Bureau calculates the mean U.S. population center every 10 years based on its national head count. The center represents the middle point of the nation's population distribution — the geographic point at which the country would balance if each of its 308.7 million residents weighed the same.
Plato, with a population of 109, is roughly 30 miles southwest of the present mean center in Phelps County, Mo. Based on current U.S. growth, which is occurring mostly in the South and West, the center of population is expected to cross into Arkansas or Oklahoma by midcentury.
The last time the U.S. center fell outside the Midwest was 1850, in the eastern territory now known as West Virginia. Its later move to the Midwest bolstered the region as the nation's cultural heartland in the 20th century, central to U.S. farming and Rust Belt manufacturing sites.