Which U.S. corn counties are most exposed to drought right now?
The U.S. Drought Exposure Monitor tracks roughly 90 million planted corn acres against federal crop-insurance coverage and the U.S. Drought Monitor's weekly severity map. The corn view is a county-by-county picture of where corn ground sits under active drought without a federal insurance backstop — refreshed every Thursday.
Where U.S. corn is grown
Corn is the largest row crop in the United States by planted area. About 90 million acres go in the ground each spring, concentrated in a band running from Ohio through Illinois, Iowa, Minnesota, Nebraska, South Dakota, and into eastern Kansas. Iowa and Illinois alone routinely account for roughly a quarter of national planted corn acreage. Outside the Corn Belt, material corn acreage shows up in the Mid-Atlantic, the Texas High Plains, and irrigated parts of the western U.S.
That concentration is why drought timing matters as much as drought severity for corn. A dry spell that hits the western Corn Belt in July — corn's pollination window — can move the national balance sheet in a way drought in a smaller-acreage region cannot. The Monitor's exposure score reflects this scale effect: a severe drought reading across a one-million-acre Iowa county weighs more heavily in the national picture than the same severity reading in a small specialty-crop county.
How drought exposure works for corn
Corn is one of the most heavily federally insured crops in the country. In major Corn Belt counties, federal crop-insurance participation typically runs around 85% of planted acres. At the national headline level, corn does not have a coverage-rate problem.
The math still bites at scale. A roughly 10% gap on 90 million planted acres is still nearly 9 million uninsured corn acres nationally. The Monitor surfaces where those uninsured corn acres are clustered, and which of those clusters happen to be in active drought this week.
The exposure score is built the same way it is for every other crop: planted acres from USDA NASS, insured acres from USDA RMA's Summary of Business, and current drought severity from the U.S. Drought Monitor. The output is a single county-level score, with corn surfaced on its own tab in the live tool.
Data sources for corn drought exposure
Every input that drives the corn exposure score is public, free, and refreshed on a known cadence:
| Source | What it provides | Refresh |
|---|---|---|
| USDA NASS | Planted corn acres by county, with three-tier waterfall for current-year coverage | Annual + intra-year revisions |
| USDA RMA Summary of Business | Federally insured corn acres by county and coverage type | Monthly mid-year + crop-year close |
| U.S. Drought Monitor | Current drought severity (D0–D4) by county | Weekly, Thursdays |
| NOAA CPC Seasonal Drought Outlook | 90-day forward outlook — development, persistence, improvement, removal | Monthly |
Frequently asked questions
Which U.S. counties grow the most corn?
Iowa and Illinois lead in planted corn acreage, with Nebraska, Minnesota, Kansas, South Dakota, and Indiana next. At the county level, the largest corn counties cluster across the western Corn Belt — central Iowa, northern Illinois, eastern Nebraska, and southern Minnesota. Outside the Corn Belt, material corn acreage shows up in the Mid-Atlantic, the Texas High Plains, and irrigated parts of the western U.S.
What is the typical federal crop insurance coverage rate for corn?
Federal crop-insurance participation for corn is among the highest of any U.S. row crop. In major Corn Belt counties, coverage rates around 85% of planted acres are common. Coverage thins in counties where corn is a secondary rotation crop, where producers rely on irrigation and self-insure against weather risk, or where premiums are high relative to historical losses.
Why does the corn coverage gap matter even when participation is high?
Corn is the largest U.S. row crop by planted area — roughly 90 million acres each year. Even a single-digit coverage gap translates into millions of uninsured acres at that scale. When those uninsured corn acres concentrate in counties that are also currently in drought, the absolute exposure can outweigh thinner-coverage but lower-acreage regions for other crops.
Where is U.S. corn most at risk from drought this week?
It changes weekly. The Monitor reorders its corn watch list every Thursday after the U.S. Drought Monitor publishes. Historically the western Corn Belt — western Iowa, Nebraska, and the Dakotas — draws the most exposure when summer drought develops, while the eastern Corn Belt across Illinois, Indiana, and Ohio tends to be wetter. The current week's view is on the live tool.