Well, the falls on the Ohio at Louisville might well encourage early explorers to travel up the Wabash and take the first large tributary to the East to see if they could find a portage. That would be the East Fork of the White River. This takes you to the Muscatatuck. It is in this basin that these peculiar brown birch trees grow.
If you keep on going East you have a short land portage to the another Ohio tributary.
However, none of these rivers are particularly deep. You would kind of dead end on this trip about Seymour, Indiana.
There you will find a major council circle of ancient vintage. The town itself is built on mounds without any buried remains or artifacts. This has frequently led folks to believe these are natural mounds. On the other hand, they are resident on about 10 square miles of perfectly flat land in the midst of a naturally rolling terrain.
The mounds are regularly spaced and shaped. You can make out the remains of ceremonial courtyards. The layout in both size and shape is very similar to Tiotihuacan.