You may be like me and wondering how on earth could anybody truly find the geographical center of a land body as diverse as the United States. Short answer, the experts cannot. But they can contrive a method that will give a good estimate, maybe within plus or minus 20 miles. They used the cardboard method back in the day, 1918, when the Coast and Geodetic Survey estimated the center to be latitude 39 degrees 50’N, longitude 98 degrees 35’W, a site near Lebanon, Kansas. Now the geographical center of the lower 48 states.
The cardboard method assumes that all the land land mass is the same thickness, which it is not (think mountains), and then cuts a diagram shape out to the approximate shape and proportions of the land mass. (Think of the ever changing coastlines due to wind, waves, and storms.) Once they have the cardboard model, they balance the cardboard looking for the center of gravity. Or think of trying to find the point where the cardboard is perfectly level when placed on the end of a pencil. That center of gravity point becomes the geographical center point.
When Alaska became a state, the new geographical center moved to latitude 63 degrees 50’N, longitude 152 degrees 00’W.
That location was short lived because Hawaii soon entered the picture and changed the model once again. However, adding Hawaii did not change the location much because Hawaii is only 1/560 of that of the other 49 states. The shift was only about 6 miles west-southwest. Or the present location near Belle Fourche.