Geode State Park is a state park of Iowa, USA, border Henry County and Des Moines County It is managed by the Iowa Department of Natural Resources. While it is named for Iowa's state rock, the geode, few can be found in the park. A display of geodes, with their mysterious crystal formations in their hollow cavities, can be seen at the park office. It is illegal to remove geodes from state parks.The prime attraction of the 1,640-acre park is Lake Geode, a 187-acre lake built in 1950.