Where is a good place to go camping in northern Illinois/southern Wisconsin?

Any place in that area that has nice places to hike and swim will be having lots of kids as well. There is a heavy concentration of Boy Scouts, Cub Scouts, Girl Scouts, and Sea Scouts in that exact area that camp on a regular basis. If you are looking to get romantic, and want to eliminate encouters of the worst kind, you will have to expand you search a bit. Kettle Moraine North State Park is a good place to get what you are looking for as a starter location.

One of the nicest places is Palisades State Park near Savana, Il. Beautiful views from bluffs of the Mississippi River, lots of trails too, some are pretty tough. There is also remote camping and a place for regular campers. If you want to swim, you would take a short trip over to Sabula, Iowa, ask at the gas station where the "swimming hole" is.