I have seen numerous farmers with farm ground in normally non-irrigated areas of the corn belt put in irrigation over the last couple of years. Based on this, I thought I would recap the trends shown in irrigated ground from the 2012 AG census
In 1997, there were 15 states that had more than a million acres of irrigated ground. The top 3 were (1) California (8.9 million acres) (2) Nebraska (7.1 million acres) and Texas (5.8 million acres).
For 2012, the number of states over 1 million increased by 2 to 17 states. Number 1 is now Nebraska at 8.3 million acres. California dropped by 1 million acres and with the continued drought, I am guessing that 2014 numbers would be even lower. The largest percentage increase in these states was Arkansas which jumped about 1 million acres to 4.8 million acres and overtook Texas for third place.
Total irrigated acreage in the US has held fairly constant at about 56 million acres from 1997 to 2012. Although small compared to other regions, the amount of irrigated ground in the three key "I" states (Illinois, Indiana and Iowa) did increase from about 740,000 acres in 1997 to about 1.13 million in 2012. I would expect to see this trend continue.
Every state has irrigated acres. I thought Delaware or Rhode Island would have the least acres, but it is actually West Virginia with slightly more than 2,000 acres. Nebraska and California each have more irrigated acres than the all of the states with less than 1 million acres (cumulative 7.4 million acres).