How the Census Bureau finds America's center of population

The Census Bureau’s center of population is a point that shows the balance of where people live in the United States. It matters because it helps visualize how the population’s location changes over time, according to the U.S. Census Bureau. The Bureau computes it after each decennial census.

What “center of population” means

The U.S. Census Bureau defines the center of population as a balance point. It 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 of one person,” according to the U.S. Census Bureau. This describes the mean center of population, where every person has equal weight on a flat map.

When and where it is calculated

According to the U.S. Census Bureau, it has calculated the center of population every 10 years since the first census in 1790, using each decennial census. The Bureau produces a national center and also centers for each state and state equivalent, each county and county equivalent, each census tract, and each census block group. These results are provided as latitude and longitude coordinates on the Centers of Population webpage.

What data files the Bureau provides

For 2020, the Census Bureau provides separate text files for national, state, county, census tract, and block group centers of population. The national files include coordinates for the mean center of population and the median center of population, according to the U.S. Census Bureau. The state file lists each state’s two-character state FIPS code, state name, 2020 Census population, and the latitude and longitude of the state’s center of population; the county files list the two-character state FIPS code, three-character county FIPS code, county name, state name, 2020 Census county population, and the latitude and longitude of the county’s center of population; the census tract files list the two-character state FIPS code, three-character county FIPS code, six-character tract code, 2020 Census tract population, and the latitude and longitude of the tract’s center of population; and the block group files list the two-character state FIPS code, three-character county FIPS code, six-character tract code, one-character block group code, 2020 Census block group population, and the latitude and longitude of the block group’s center of population.

Mean, median, and other reference points

The Census Bureau publishes both a mean center of population and a median center of population for the nation, according to the U.S. Census Bureau. It also posts a visualization that shows the positions of the geographic center of area, the mean center of population, and the median center of population for 2020. Documentation describing the computation methodology used from 1950 to 2020 is available on the Centers of Population page.

The 2020 national center

As of the 2020 Census, the national mean center of population is at 37.415725 N, 92.346525 W, according to the U.S. Census Bureau. The Bureau reports that this is the most western and southern national mean center of population point in the nation’s history, 11.8 miles from the 2010 location and 885.9 miles from the 1790 location. Hartville, Missouri, is the nearest incorporated municipality to the 2020 center, and the Census Bureau notes it is a town of 594 people in Wright County, Missouri.

How the center has shifted over time

The U.S. Census Bureau provides maps and plots showing the national mean center of population for 1790 to 2020 and the median center from 1880 to 2020. It reports that the farthest leap in distance between centers came between 1850 and 1860, a shift of 103 miles, and the slowest movement was between 1910 and 1920 when it shifted 10 miles. A Bureau plot also highlights the decade with the most northerly direction (1870) and the most southerly (2020).

How to see the results

The Census Bureau hosts maps and interactive visualizations that illustrate centers of population for 2020 and trace national shifts across decades. It also offers a story map collection with information about historic centers of population, the 2020 centers, and commemorative marks. According to the U.S. Census Bureau, downloadable text files provide the coordinates and related identifiers for each level from the nation down to block groups.