I'm not familiar with Rock River IL, but but if you use this in a river, make sure you have it secured some how....with it being round in shape, the river current might just push it down stream.
Securing it it easy tho.
take a snap from your tackle box & attach it to one end.
take a rope, 80# fishing line, or a small chain & attach it to the snap.
Take the other end of this line & attach it to something on shore that will not move...like a tree.
Give the trap about 12 hours & by then it should be full.