Map showing changes to the mean center of population for the United States, 1790–2010 (US Census Bureau)
[ 1]
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 point at which an imaginary, flat, weightless, and rigid map of the United States would balance perfectly if weights of identical value were placed on it so that each weight represented the location of one person on the date of the census.[ 2]
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 [ edit ]
US Census
County
Location description[ 3]
Decimal coordinates[ 3]
1790
Kent County, Maryland 1.)
23 miles east of Baltimore.
39°16′30″N 76°11′12″W / 39.27500°N 76.18667°W / 39.27500; -76.18667
1800
Howard County, Maryland
18 miles west of Baltimore.
39°16′06″N 76°56′30″W / 39.26833°N 76.94167°W / 39.26833; -76.94167
1810
Loudoun County, Virginia
40 miles northwest by west of Washington, DC.
39°11′30″N 77°37′12″W / 39.19167°N 77.62000°W / 39.19167; -77.62000
1820
Hardy County, Virginia (now W. Virginia) 2.)
16 miles east of Moorefield.
39°05′42″N 78°33′00″W / 39.09500°N 78.55000°W / 39.09500; -78.55000
1830
Grant County, Virginia (now W. Virginia) 2.)
19 miles west-southwest of Moorefield.
38°57′54″N 79°16′54″W / 38.96500°N 79.28167°W / 38.96500; -79.28167
1840
Upshur County, Virginia (now W. Virginia) 2.)
16 miles south of Clarksburg.
39°02′00″N 80°18′00″W / 39.03333°N 80.30000°W / 39.03333; -80.30000
1850
Wirt County, Virginia (now W. Virginia) 2.)
23 miles southeast of Parkersburg.
38°59′00″N 81°19′00″W / 38.98333°N 81.31667°W / 38.98333; -81.31667
1860
Pike County, Ohio
20 miles south by east of Chillcothe.
39°00′24″N 82°48′48″W / 39.00667°N 82.81333°W / 39.00667; -82.81333
1870
Highland County, Ohio
48 miles east by north of Cincinnati.
39°12′00″N 83°35′42″W / 39.20000°N 83.59500°W / 39.20000; -83.59500
1880
Boone County, Kentucky
8 miles west by south of Cincinnati.
39°04′08″N 84°39′40″W / 39.06889°N 84.66111°W / 39.06889; -84.66111
1890
Decatur County, Indiana
20 miles east of Columbus.
39°11′56″N 85°32′53″W / 39.19889°N 85.54806°W / 39.19889; -85.54806
1900
Bartholomew County, Indiana
6 miles southeast of Columbus.
39°09′36″N 85°48′54″W / 39.16000°N 85.81500°W / 39.16000; -85.81500
1910
Monroe County, Indiana
in the city of Bloomington.
39°10′12″N 86°32′20″W / 39.17000°N 86.53889°W / 39.17000; -86.53889
1920
Owen County, Indiana
8 miles south-southeast of Spencer.
39°10′21″N 86°43′15″W / 39.17250°N 86.72083°W / 39.17250; -86.72083
1930
Greene County, Indiana
3 miles northeast of Linton.
39°03′45″N 87°08′06″W / 39.06250°N 87.13500°W / 39.06250; -87.13500
1940
Sullivan County, Indiana
2 miles southeast by east of Carlisle.
38°56′54″N 87°22′35″W / 38.94833°N 87.37639°W / 38.94833; -87.37639
1950
Richland County, Illinois 3.)
8 miles north-northwest of Olney. 3.)
38°50′21″N 88°09′33″W / 38.83917°N 88.15917°W / 38.83917; -88.15917 3.)
1950
Clay County, Illinois 4.)
3 miles northeast of Louisville. 4.)
38°48′15″N 88°22′08″W / 38.80417°N 88.36889°W / 38.80417; -88.36889 4.)
1960
Clinton County, Illinois 5.)
6-1/2 miles northwest of Centralia. 5.)
38°35′58″N 89°12′35″W / 38.59944°N 89.20972°W / 38.59944; -89.20972 5.)
1970
St. Clair County, Illinois
5 miles east-southeast of Mascoutah.
38°27′47″N 89°42′22″W / 38.46306°N 89.70611°W / 38.46306; -89.70611
1980
Jefferson County, Missouri
1/4 mile west of DeSoto.
38°08′13″N 90°34′26″W / 38.13694°N 90.57389°W / 38.13694; -90.57389
1990
Crawford County, Missouri
9.7 miles southeast of Steelville.
37°52′20″N 91°12′55″W / 37.87222°N 91.21528°W / 37.87222; -91.21528
2000
Phelps County, Missouri
2.8 miles east of Edgar Springs
37°41′49″N 91°48′34″W / 37.696987°N 91.809567°W / 37.696987; -91.809567 [ 4]
2010
Texas County, Missouri
2.7 miles northeast of Plato.
37°31′03″N 92°10′23″W / 37.517534°N 92.173096°W / 37.517534; -92.173096 [ 5]
2015 (estimated)
Wright County, Missouri
8.0 miles southwest of Plato.
37°26′26″N 92°20′47″W / 37.440431°N 92.346373°W / 37.440431; -92.346373 [ 6]
2020 (projected)
Wright County, Missouri
8.3 miles north of Hartville.
37°22′14″N 92°30′11″W / 37.370671°N 92.503147°W / 37.370671; -92.503147 [ 6]
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.[ 6]
Notes on the table data
In the first census (1790) the mean population center was near Chestertown, Maryland .[ 4]
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.[ 4]
Computation method used until 1950.
Current computation method.
The addition of Alaska and Hawaii to the union moved the center about two miles (3 km) farther south and about ten miles (16 km) farther west in 1960.[ 3]
See also [ edit ]
References [ edit ]