The mean center of U.S. population is determined by the United States Census Bureau from the results of each census. The Bureau defines it to be:
After moving roughly 600 mi (966 km) West by south during the 19th century, during the 20th century the shift in the mean center of population was less pronounced, moving 324 mi (521 km) west and 101 mi (163 km) south. The southerly movement was much stronger during the second half of the 20th century; 79% of the southerly movement happened between 1950 and 2000.
The 14.6 mile shift projected for the 2010–2020 period would be the shortest centroid movement since the intercensal period of 1910–1920.