The mean center of the United States population is determined by the United States Census Bureau from the results of each national census. The Bureau defines it as follows:
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, the shift in the mean center of population during the 20th century was less pronounced, moving 324 mi (521 km) west and 101 mi (163 km) south. Nearly 79% of the overall southerly movement happened between 1950 and 2000.
Location information since 1790
|US Census||County||Location description||Decimal coordinates||Distance from previous point|
|1790||Kent County, Maryland[a]||23 miles east of Baltimore||n/a|
|1800||Howard County, Maryland||18 miles west of Baltimore||52 miles (84 km)|
|1810||Loudoun County, Virginia||40 miles west-northwest of Washington, D.C.||47 miles (75 km)|
|1820||Hardy County, West Virginia[b]||16 miles east of Moorefield||64 miles (103 km)|
|1830||Grant County, West Virginia[b]||19 miles west-southwest of Moorefield||51 miles (81 km)|
|1840||Upshur County, West Virginia[b]||16 miles south of Clarksburg||70 miles (113 km)|
|1850||Wirt County, West Virginia[b]||23 miles southeast of Parkersburg||70 miles (113 km)|
|1860||Pike County, Ohio||20 miles southeast of Chillicothe||103 miles (166 km)|
|1870||Highland County, Ohio||48 miles northeast of Cincinnati||54 miles (87 km)|
|1880||Boone County, Kentucky||8 miles southwest of Cincinnati||74 miles (119 km)|
|1890||Decatur County, Indiana||20 miles east of Columbus||61 miles (99 km)|
|1900||Bartholomew County, Indiana||6 miles southeast of Columbus||18 miles (30 km)|
|1910||Monroe County, Indiana||in the city of Bloomington||50 miles (80 km)|
|1920||Owen County, Indiana||8 miles south-southeast of Spencer||13 miles (20 km)|
|1930||Greene County, Indiana||3 miles northeast of Linton||29 miles (46 km)|
|1940||Sullivan County, Indiana||2 miles east-southeast of Carlisle||17 miles (27 km)|
|1950||Richland County, Illinois[c]
Clay County, Illinois[d]
|8 miles north-northwest of Olney
3 miles northeast of Louisville
|54 miles (87 km)|
69 miles (110 km)
|1960||Clinton County, Illinois[e]||6.5 miles northwest of Centralia||58 miles (93 km)|
|1970||St. Clair County, Illinois||5 miles east-southeast of Mascoutah||34 miles (55 km)|
|1980||Jefferson County, Missouri||0.3 mile west of DeSoto||60 miles (96 km)|
|1990||Crawford County, Missouri||9.7 miles southeast of Steelville||44 miles (71 km)|
|2000||Phelps County, Missouri||2.8 miles east of Edgar Springs||||41 miles (66 km)|
|2010||Texas County, Missouri||2.7 miles northeast of Plato||||25 miles (40 km)|
|2020 (Census Day estimation)||Wright County, Missouri||9.0 miles north northeast of Hartville||||18.3 miles (29.4 km)|
- In the first census (1790), the mean population center was about 7.4 miles northwest by west of Chestertown, Maryland.
- The mean population centers of 1820, 1830, 1840 and 1850 were in Virginia at the time of their censuses, before 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 in 1959 contributed to moving the mean center of population about 2 miles (3.2 km) farther south and about 10 miles (16 km) farther west in the 1960 census.
- "Mean Center of Population for the United States: 1790 to 2010" (PDF). Archived from the original (PDF) on January 30, 2013.
- Centers of population computation, a U.S. Census Bureau publication, issued March 2011.
- 2000 U.S. Population Centered in Phelps County, Mo. Archived December 22, 2012, at the Wayback Machine, a U.S. Census Bureau press release.
- Centers of Population for the 2010 Census, U.S. Census Bureau.
- Alex Zakrewsky, Principal Planner, Middlesex County New Jersey Office of Planning.