Forest, Not Corn: Deer Harvest per Square Mile in Five Midwest States

Across 462 counties in Iowa, Illinois, Missouri, Ohio and Wisconsin, counties with more forest tended to register more deer per square mile from 2020 to 2024. The link is steepest in Iowa, where the most-forested quarter of counties averaged 3.82 deer per square mile against 0.55 in the least-forested quarter, and weakest in Wisconsin, where the same comparison is 6.93 against 5.44. These are deer that hunters registered, so the numbers reflect effort and access as well as deer, and they describe a pattern across counties without explaining it.

Deer harvested per square mile is the number of deer hunters registered in a county, divided by the county's land area in square miles. Dividing by area puts a small county and a large one on the same scale, which a raw county total cannot do. We averaged the seasons from 2020 to 2024 so that one odd year does not set a county's score, and we took land area from the USDA Cropland Data Layer county summaries. The same source gives each county's forest share, meaning the part of its land mapped as deciduous, mixed or evergreen forest, and its share in corn and soybeans.

Iowa is where the pattern is cleanest. Rank its 99 counties by forest share and by harvest per square mile and you get nearly the same order, a rank correlation of +0.92. Rank them by corn and soybean share and you get nearly the opposite order, at -0.90. Split the counties into quarters by forest share and the gap is wide. The least-forested quarter, averaging 1.0% forest, registered 0.55 deer per square mile. The most-forested quarter, averaging 21.1% forest, registered 3.82. That is a ratio of 7.0x.

An Iowa county in the "most-forested" quarter is not heavily wooded. Its quarter averages 21.1% forest, against 34.7% for Illinois's most-forested quarter and 47.9% for Wisconsin's. The 7.0x also reflects how low Iowa's bottom is: its least-forested quarter registers fewer deer per square mile than the least-forested quarter of any other state here, and its most-forested quarter, at 3.82, is the lowest top of the five. The split matches our earlier look at The Two Iowas, which found the harvest concentrated in a timber-and-river northeast and far lighter across the corn-and-soybean northwest.

Illinois follows Iowa at 3.7x, from 1.28 deer per square mile in its least-forested quarter to 4.70 in its most-forested. Ohio comes next at 2.7x (2.66 to 7.15), then Missouri at 1.8x (2.68 to 4.75).

A rank correlation compares two orderings of the same counties. A high positive value means the counties with the most forest are, nearly in order, the counties with the highest harvest per square mile. A value near zero means the forest ordering says little about the harvest ordering.

Missouri shows why the ratio depends on the floor as well as the ceiling. Its most-forested quarter averages 69.3% forest, far above Iowa's 21.1%, yet its ratio is only 1.8x, because even its least-forested quarter (12.1% forest) registers 2.68 deer per square mile.

Wisconsin's forest ranking correlates with harvest per square mile at only +0.29, and its corn-and-soy ranking at -0.14. The most-forested quarter of its 60 counties, averaging 47.9% forest, registered 6.93 deer per square mile. The least-forested quarter, averaging 6.6% forest, registered 5.44. That is 1.3x, and the lower figure is higher than the most-forested quarter in Iowa, Illinois or Missouri.

The top of the county list shows the mix. Green Lake, at 9% forest and 31% corn and soy, ranks seventh of all 462 counties at 11.13. Vernon, at 46% forest and 17% corn and soy, ranks eleventh at 10.62. Hunters registered many deer per square mile in both kinds of country.

Our data cannot say why Wisconsin behaves differently. Tag policy is one candidate: The Density Paradox describes liberal, often unlimited, antlerless tags in the state's southern farmland zone. We did not test that here.

Eight of the 15 counties with the highest harvest per square mile are in Ohio and seven are in Wisconsin. No county from Iowa, Illinois or Missouri appears. Marquette, Wisconsin leads at 15.15 (27% forest, 19% corn and soy), and Coshocton, Ohio is second at 13.20. Five of Ohio's eight are more than half forest: Coshocton (58%), Carroll (56%), Tuscarawas (54%), Harrison (62%) and Guernsey (64%). Of Wisconsin's seven, only Richland, at 51%, is above half.

The harvest counts are each state agency's registered deer harvest by county, averaged over 2020 to 2024, for 99 counties in Iowa, 102 in Illinois, 113 in Missouri, 88 in Ohio and 60 in Wisconsin. Harvest per square mile reflects hunter effort and access as well as deer numbers. It is not a population estimate, and a high score means only that hunters registered many deer for each square mile.

The quarters are the quarter of each state's counties with the least forest and the quarter with the most, so every state is compared with itself. Ratios come from the unrounded county averages, so dividing two rounded figures in the table can land a tenth away from the printed ratio.

A correlation across counties shows that two things line up, and it cannot show that forest explains the harvest. Forest and cropland compete for the same acres, so a county with more of one has less of the other, and these data cannot separate "more forest" from "less crop." We also did not measure hunter numbers or land access, either of which could move with cover.

Use forest share as a first filter in Iowa, Illinois and Ohio, where it lines up with harvest per square mile at +0.92, +0.86 and +0.76. Between two otherwise similar counties, the one with more cover has more often been the one where hunters registered more deer per square mile. Use it lightly in Missouri (+0.52). In Wisconsin (+0.29), skip it and compare counties on harvest history and access.

Once you have a shortlist, test each county's reputation against its records before you believe it, as Buying Deer Ground shows for land buyers. To learn whether the county that leads a state's raw totals is also first per square mile, read The County That Kills the Most Deer Isn't Always Top per Square Mile, which uses the same per-square-mile measure.