Flood Risk in Gallatin County, Illinois: A History Severe Enough to Move the County Seat

A 19th-century flood sequence that led to the first levees

Shawneetown's location directly on the Ohio River made it vulnerable from its earliest years. Major floods struck in 1832, 1847, 1853, and 1858, and the flood of 1859 was severe enough to convince residents of the need for organized flood control. Construction on a levee system began in 1883 -- but the levee wasn't even finished when the river overpowered it in February 1884, pouring floodwater into the town anyway. The years that followed saw a pattern that would repeat for over a century: a levee built, a levee destroyed by a flood, and a larger, firmer one built in its place.

The 1898 flood, and the 1937 flood that relocated the town

The 1898 flood was one of the most catastrophic events in Shawneetown's history: the Ohio River flooded dozens of square miles in and around the town with water reported up to 15 feet deep. This research pass found inconsistent figures for the resulting death toll across different sources, so none is stated here with confidence -- but the flood's scale and the depth of water it produced are consistently documented.

The most consequential flood in the town's history, though, came in 1937. The Ohio River flood that year -- part of the broader, historically severe Ohio Valley flood of January-February 1937 -- inundated the original Shawneetown townsite so completely that the town relocated to its present location that same year, leaving the historic original site to survive today as the separate, much smaller community of Old Shawneetown. Few Illinois towns have a flood history severe enough to have actually moved the town rather than simply rebuilding it in place -- that's the fact pattern that makes Gallatin County's flood risk different from a typical mapped-floodplain story.

The risk today: the 2011 flood and ongoing levee dependence

The risk isn't purely historical. During the 2011 flood, the Ohio River crested at 56.85 feet at Old Shawneetown -- flood stage there is 33 feet -- and the Illinois National Guard was deployed to walk the levee as residents were evacuated from Old Shawneetown, according to contemporaneous local news reporting. That's a reminder that the area's flood protection today still depends on levee performance, the same basic dynamic that has driven the county's flood history for nearly two centuries.

For anyone evaluating land near the Ohio River in Gallatin County -- and especially near Old Shawneetown specifically, given its history and lower elevation relative to the relocated town -- that recurring levee-dependent pattern is worth weighing well beyond a single FEMA flood-zone lookup for a specific parcel.

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 Gallatin County Supervisor of Assessments -- who also serves as the county's Flood & Zoning Officer -- whether the parcel or its access road has a documented history of flooding or levee-related closure, particularly for anything near Old Shawneetown or the Ohio River bottomland generally.

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 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.