I lived in Rockton Illinois from ’87-’92. I targeted large flatheads on the Rock and did very well. I would use small bluegills for bait. My best tactic was to anchor on the downriver side of a bridge piling, and cast the ‘gill out into the current. The bait would be swept into an area with less current. I never worried about watching the poles, because when I had a bite, the big flats would inhale the gill. I was never skunked, but had many nights where I caught only one flat. I would also fish for channels with pieces of fresh shrimp. Channels love fresh shrimp. One medium shrimp would give me 4 pieces of bait. Back then, I was always reminded of the novel, “The Old Mand and the Sea.” I had a 12’ alumacraft and usually fished alone. Pulling in a 25 pound flat in the dark was quite exciting.
Downriver below Rockford and farther south to the Dixon area, big flats are targeted heavily.