Mean center of the United States population
The mean center of the United States population is determined by the United States Census Bureau from the results of each census. The Bureau defines it to be:
The concept of the center of population as used by the U.S. Census Bureau is that of a balance point. The center of population is the point at which an imaginary, weightless, rigid, and flat (no elevation effects) surface representation of the 50 states (or 48 conterminous states for calculations made prior to 1960) and the District of Columbia would balance if weights of identical size were placed on it so that each weight represented the location on one person. More specifically, this calculation is called the mean center of population.
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.
Location info since 1790
|US Census||County||Location description||Decimal coordinates|
|1790||Kent County, Maryland 1.)||23 miles east of Baltimore.|
|1800||Howard County, Maryland||18 miles west of Baltimore.|
|1810||Loudoun County, Virginia||40 miles northwest by west of Washington, DC.|
|1820||Hardy County, Virginia (now W. Virginia) 2.)||16 miles east of Moorefield.|
|1830||Grant County, Virginia (now W. Virginia) 2.)||19 miles west-southwest of Moorefield.|
|1840||Upshur County, Virginia (now W. Virginia) 2.)||16 miles south of Clarksburg.|
|1850||Wirt County, Virginia (now W. Virginia) 2.)||23 miles southeast of Parkersburg.|
|1860||Pike County, Ohio||20 miles south by east of Chillcothe.|
|1870||Highland County, Ohio||48 miles east by north of Cincinnati.|
|1880||Boone County, Kentucky||8 miles west by south of Cincinnati.|
|1890||Decatur County, Indiana||20 miles east of Columbus.|
|1900||Bartholomew County, Indiana||6 miles southeast of Columbus.|
|1910||Monroe County, Indiana||in the city of Bloomington.|
|1920||Owen County, Indiana||8 miles south-southeast of Spencer.|
|1930||Greene County, Indiana||3 miles northeast of Linton.|
|1940||Sullivan County, Indiana||2 miles southeast by east of Carlisle.|
|1950||Richland County, Illinois 3.)||8 miles north-northwest of Olney. 3.)||3.)|
|1950||Clay County, Illinois 4.)||3 miles northeast of Louisville. 4.)||4.)|
|1960||Clinton County, Illinois 5.)||6-1/2 miles northwest of Centralia. 5.)||5.)|
|1970||St. Clair County, Illinois||5 miles east-southeast of Mascoutah.|
|1980||Jefferson County, Missouri||1/4 mile west of DeSoto.|
|1990||Crawford County, Missouri||9.7 miles southeast of Steelville.|
|2000||Phelps County, Missouri||2.8 miles east of Edgar Springs|||
|2010||Texas County, Missouri||2.7 miles northeast of Plato.|||
|2015 (estimated)||Wright County, Missouri||8.0 miles southwest of Plato.|||
|2020 (projected)||Wright County, Missouri||8.3 miles north of Hartville.|||
The 20.8 mile shift projected for the 2010–2020 period would be the shortest centroid movement since the Great Depression intercensal period of 1930–1940.
Notes on the table data
- In the first census (1790) the mean population center was near Chestertown, Maryland.
- The mean population centers of 1820, 1830, 1840 and 1850 were in what is now West Virginia, given West Virginia's split from Virginia in 1863.
- Computation method used until 1950.
- Current computation method.
- The addition of Alaska and Hawaii to the union contributed to move the center about two miles (3 km) farther south and about ten miles (16 km) farther west in 1960.
- Center of population
- Median center of United States population
- Geographic center of the United States
- Geographic center of the contiguous United States
- Mean Center of Population for the United States: 1790 to 2010 from the U.S. Census Bureau website.
- Centers of population computation, a U.S. Census Bureau publication, issued March 2011.
- 2000 U.S. Population Centered in Phelps County, Mo., a U.S. Census Bureau press release.
- Centers of Population for the 2010 Census, U.S. Census Bureau.
- Alex Zakrewsky, Principal Planner/Data Manager, Middlesex County New Jersey Office of Planning.