The borders of Illinois have been altered on a number of occasions – sometimes by the decisions of man, and at least once by the power of Mother Nature.
When Illinois became a territory the capital was established at Kaskaskia. Never heard of Kaskaskia, Illinois? It might be because it hasn’t been the capital since 1819, currently has only about 14 residents, and many years ago literally became detached from Illinois.
Set right on the banks of the Mississippi River, Kaskaskia became the victim of the power of the changing course of a mighty river. The need for wood for building caused massive deforestation of that stretch of the river banks and in 1881 floods destroyed most of the town of Kaskaskia. When the waters receded, the river had redirected itself into a new channel … which separated the town from the state of Illinois.
To this day, the only way to get to Kaskaskia, Illinois is through Missouri. The postal department has assigned it a Missouri zip code because it is only through Missouri that letter carriers can make the trip across the bridge that spans the old riverbed. Virtually none of the original buildings stand, but a handful of residents remain in the old town and look across the river at their state.