People like to find the center of things- the center of a baseball, the center of the Earth, the center of the universe, the center of a Tootsie Pop.
Our fascination with the center of things has led to incredible scientific discoveries like orbits of planets and movements of stars; lesser known discoveries have led us to understand how many licks it takes to get to the center of a jawbreaker.
There is some debate as to the center of things that aren’t necessarily round or easily measured. People have argued for years about the geographic center of the contiguous United States, for example.
Measurements on land masses are especially difficult to obtain because of the fluidity of shorelines, which can change and erode rapidly in some places.
In the case of the United States there are also two different ways people choose to measure the center- some include the states of Hawaii and Alaska, which were added to the country after the first geographic center measurement was taken; this first measurement only included the lower 48 states which dramatically shifted the geographic center’s location.
Original Calculation of the Geographic Center of the Continental United States
The original geographic center of the contiguous United States has long been considered to be about 2.6 miles northwest of the town of Lebanon, Kansas. The GPS coordinates are 39°50′N 98°35′W.
This measurement was taken in 1918 by the U.S. National Geodetic Survey and included the states of Arizona and New Mexico, which were added to the lower 48 states in 1912. This was seen as the most complete United States calculation at the time.
The U.S. National Geodetic Survey, or NGS, didn’t have complex digital methods of determining the geographic center of the United States at the time. Instead they used a cardboard cutout of the nation and balanced it on the head of a pin- where the cutout balanced perfectly was taken down as the geographic center of the nation.
Now, this obviously isn’t a very good method for determining a country’s geographic center! The NGS used the materials they had and ended up with a center measurement that was accurate to 20 miles. The coordinates for the geographic center were nearest to the town of Lebanon but were actually located slightly outside of town in a local hog farm. To protect the owner of the hog farm from tourists plaguing his land, a plaque denigrating the geographic center of the US was placed in its current location about half a mile away in 1940.
The geographic center of the United States was immortalized in Neil Gaiman’s fictional book, American Gods. The place today contains a small chapel, plaque and an American flag.
Geographic Center of the Entire United States
The geographic center of the United States taking Alaska and Hawaii into the equation is located near a town called Belle Fourche, South Dakota.
Although the NGS no longer maintains a stance on where the geographic center of the US is, this is widely considered the more accurate measurement. This geographic center is located about 20 miles north of Belle Fourche at latitude 44 58 02.07622 (N) and longitude 103 46 17.60283 (W).
This location is also marked with a plaque from the NGS and an American flag, although the exact measured center is located nearby and is only marked by an underground slab of concrete in a nearby pastureland.
The difference between the 1918 measurement and the more recent measurement is about 550 miles.
Despite the more accurate measurement of the more recent geographic center (that of Belle Fourche in South Dakota), the precise geographic center of the United States may simply be too hard to determine.
A consistent opinion on shorelines needs to be obtained by the NGS and other interested bodies in order to have a concentrated approach to measuring the center of the United States taking erosion and shoreline change into consideration or not.
The existence of an accurate geographic center of the US doesn’t matter to a lot of people, and yet for others finding the true center is the ultimate goal. While many of us might not see the appeal of going to Lebanon, Kansas or Belle Fourche, South Dakota to take a picture next to a plaque, the historical and geographical significance of these two places can serve as reminders of how the nation has physically changed during its existence.
2015 Calculation of the Geographic Center of the United States
The geographic center of the United States has been a long-contested metric. Finding the geographic center of a city, country, or continent is challenging because there are a variety of ways to go about calculating this geographic place. Some geographers add in bodies of water to their geographic calculations, while others choose to leave out bodies of water or islands.
The U.S. Geological Survey recognized the complexities of determining geographic centers and said that there was no one way to calculate this center. Back in 1964 the agency published a report on the centers of states, noting “There is no generally accepted definition of geographic center, and no completely satisfactory method for determining it.”
For Peter Rogerson, PhD, at the University of Buffalo, this challenge wasn’t a reason why he wasn’t going to try to find the best way of calculating the geographic center of each of the states of the United States.
Rogerson published a paper in 2015 in The Professional Geographer describing his new approach to finding the center of a spatial entity. He used his method to pinpoint the center of the 48 contiguous United States stating:
The geographic center of the contiguous forty-eight states (plus the District of Columbia) is at 39.8355 N, 99.0909 W. This location in Kansas is 5.3 miles from Agra and 5.5 miles from Kensington, at the intersection of East 1300 Road and East Mohawk Road. It lies 29.5 great circle miles west of the long-standing designated center of Lebanon, Kansas.
Finding the geographic center of a spatial entity might seem like a fool’s errand, but the theoretical center of a state or city used to be how people chose where their seat of political power would be. Most people seem to be interested in the center of their city or state as a point of interest, or as another landmark that makes the geographical area around them special.
More technically complex than using a cardboard cutout that that the USGS employed in the 1960s, Rogerson’s new method takes into consideration the curvature of the Earth when assessing a geographic center. Rogerson utilized the azimuthal equidistance map projection in his equations.
Barmore, F. E. (1994). Center Here; Center There; Center, Center Everywhere!. https://deepblue.lib.umich.edu/bitstream/handle/2027.42/60202/Reprint94BarmoreA.pdf
Geographic Center of the United States (n.d.) National Oceanic and Atmospheric Administration. https://www.ngs.noaa.gov/PUBS_LIB/GeoCenter_USA1.pdf
Richeson, D. (2005). Centers of the United States. The College Mathematics Journal, 36(5), 366-373. https://www.tandfonline.com/doi/pdf/10.1080/07468342.2005.11922151
Rogerson, P. A. (2015). A New Method for Finding Geographic Centers, with Application to US States. The Professional Geographer, 67(4), 686-694.