Flood Risk and Access in Calhoun County, Illinois

The geography: a peninsula between two rivers

Calhoun County occupies a roughly 37-mile-long, 5-mile-wide tongue of land at the point where the Illinois River joins the Mississippi, connected to the rest of Illinois by only about 17 miles of land at its northern end. That geography is exactly why flooding here is a different kind of risk than in most rural counties: high water on either river doesn't just threaten low-lying farmland along a floodplain edge, it can affect the county's only road and bridge connection to the outside world.

The 1993 flood: nearly 40% of the county underwater

During the Great Flood of 1993 -- the historic flood event that inundated an estimated 15 million-plus acres of farmland across the Upper Midwest -- nearly 40% of Calhoun County was submerged, according to The Telegraph's 25-years-later retrospective reporting. The villages of Hamburg and Mozier were the first swamped, with much of Kampsville, Hardin, and Golden Eagle following. The Nutwood levee, which sits across the Illinois River in neighboring Jersey/Greene County and protects the land approach to the Joe Page Bridge (the county's only bridge), failed outright on July 18, 1993.

Floodwater in Calhoun County that summer did not recede below flood stage until November -- a multi-month event, not a short-duration spike. That duration matters for anyone evaluating land here: a "100-year flood" designation on a map doesn't capture how long water can actually sit on low ground in this geography once a flood event starts.

The 2019 flood: when the levee closed the only road out

The risk isn't historical only. During the 2019 flood, the Nutwood levee was overtopped on June 3, after rising water had already forced the closure of the county's ferries. That overtopping shut down IL Route 100 -- the sole road connecting to the Joe Page Bridge, itself the county's only bridge -- and residents reportedly had to boat in and out of the county for roughly six weeks before road access was restored, per RiverBender.com's contemporaneous reporting.

That's the fact pattern worth internalizing before buying land in Calhoun County: it isn't just that a specific parcel might sit in a mapped floodplain (check that directly, as you would anywhere), it's that a flood event severe enough to overtop a levee miles away can cut off the entire county's land access for weeks at a time. If a planned use depends on reliable daily access -- a business, a rental property, livestock that needs regular feed deliveries -- build that access risk into your planning, not just the flood risk to the parcel itself.

What to check before buying

Start with a current FEMA Flood Insurance Rate Map (FIRM) lookup for the specific parcel, which will show whether it sits in a mapped Special Flood Hazard Area and what that means for federally backed mortgage flood-insurance requirements. Separately, ask the Calhoun County Building Inspector's office whether the parcel or its access road has a documented history of closure during high water -- village-level and county-level institutional memory here (per the events above) tends to be specific and well-informed, even where it isn't captured on a FEMA map.

If any construction is planned within a mapped floodway (as opposed to just a flood-hazard area), a floodway construction permit from IDNR's Office of Water Resources may be required in addition to any county building permit -- this is a state-level permit distinct from FEMA flood insurance and from county zoning. See our national flood-zones guide for the general FEMA/NFIP framework this fits into.