DeSoto Bend/ DeSoto National Wildlife Refuge is a great place to watch wildlife, especially birds, hike, fish, hunt, boat, picnic, etc. My favorite thing to do is go to the museum in the visitor center and to see where the steamship Bertrand wrecked. It is now located in a lake but it used to be part of the Missouri River (the river changed direction several times). The Bertrand sunk in 1865 and was discovered in 1968. The wreck was excavated and then the lake was allowed to reclaim it. The artifacts can be seen in the visitor center. The boat was filled with food and supplies headed to the goldmines in the west so some of the artifacts include jarred food!
DeSoto Bend is a little more than 1/2 hour north of Council Bluffs. Go to Missouri Valley and head west. Entrance fee is $3.00/ car but it's a federal fee so the new National Parks passes should cover it.