I took it up on myself to see exactly how much space Corn Fields occupy in each state, and the results are quite interesting.
Here are the top 3 Corn states by surface area occupied by Corn
1. Iowa 36.4% 2. Illinois 29.7% 3. Indiana 23.6%
The US also is one of the top producers of Soybeans, Wheat, and Cotton, which also occupy much of the Midwest and Plains, but not as much as corn does. To see those maps, please see this blog post! :)