All four of the states listed here increased corn acres by more than one million acres since 1999. Iowa had the largest increase with 1.6 million acres, but in terms of a percentage increase, North Dakota easily wins with almost 140% more acres this year vs. 1999. The next state in line with the greatest increase in corn acres was Kansas. Think about the large increase in corn acres in the Dakotas and Kansas, and you can picture the cornbelt creeping west into traditional wheat territory.