Cycler68, I have not tried either of those rivers. I didn't even know Iowa had a Rock River! I lived in northern Illinois for a time, and there is a Rock River there that definitely has a good population of Smallies.

Malevo, You may have seen these pics on Chad's Iowa Fly Fishers site, I listed the name of the river there. Yes, I think you know this river well. 18-inchers? Those would be HUGE from this river! About 3-4 years ago (before the drought summers), there was a feedlot manure pond spill into the upper reaches of this river which resulted in an extensive fish kill. The DNR said they found Smallies as large as 20" there, which really surprised me.