Puzzles me too Ted. The article was very sparse in giving place names. It is possible it’s Cairo IL — hard to tell from the map — because they also talk about portages where goods were loaded and unloaded at major river confluences, so that would mean the Ohio and the Miss.

Yes St. Anthony Falls is the only ‘true’ falls (geologically speaking) on the Miss. but there were at least three other barriers/impediments to navigation — not falls — but rapids which have since been blasted away I guess. These were at St. Louis, Keokuk IA and Rock Island IL. The article only mentions Keokuk but that’s obviously not where the portage line is on the map.