There was apparently a lot of interconnection up and down the river between St Louis and New Orleans
Iccluding Fort Kaskaskia in Ill, and the old settlements at Cahokia, IL, as well as the towns of St Genevieve and Cape Girardeau in Mo as well as other smaller communities

My sister-in-law's family descends from some of the old French names there --- Bova/Bovey/Beauvais, DeRousse, Henault, Louveau, Monreau

This site has Perry County MO
and lots of good links