While the center of the contiguous United States is marked by a small plaque and plinth in Kansas, the actual center of the United States (including Hawaii and Alaska) is off in a field in South Dakota. Oh, but the actual monument is about 20 miles away from that.
Hawaii became the last U.S. state to join the union in 1959. Previously the middle of the nation had been mapped as a spot in Lebanon, Kansas, but this point moved over 200 miles with the addition of the island state. The new spot was determined to be out in the middle of some South Dakota farmland, where a metal pole was driven into the ground to mark the location.
This seemed like kind of a weak way to honor the very middle of America, so the city of Belle Fourche, a little over 20 miles south of the makeshift marker, decided to do it up right.