Lebanon, Kansas, the geographic center of the contiguous United States is the center of 48 U.S. states. It has been regarded as such by the U.S. National Geodetic Survey (NGS) since the 1912 additions of New Mexico and Arizona to the United States.
I love this part : In 1918, the Coast and Geodetic Survey found this location by balancing on a point a cardboard cutout shaped like the U.S. Incredibly, this method was accurate to within twenty miles, but while the Geodetic Survey no longer endorses any location as the center of the U.S., the identification of Lebanon, Kansas has remained.