Northern Missouri
The Thompson and Grand River bottoms bring flood questions
Grundy County drains through the Thompson River into the Grand River system, so bottomland property can sit in a mapped flood zone with insurance implications.
The Thompson River and the Grand River give Grundy County some of its broad bottomland. Those flat fields can be good ground, but low land near the rivers can also fall inside an official flood zone.
For a buyer, the map matters parcel by parcel. Land in a Special Flood Hazard Area may require flood insurance for a federally backed home loan. Even without a loan rule, a low spot can still flood in a wet year.
Use the FEMA Flood Map Service Center for the address or parcel, not just a general county map. Then ask the county which local floodplain rules apply before building, filling, or placing a structure near the river.
Missouri SEMA is the state emergency source, and the USGS river gauge helps show how the river system behaves over time. Neither replaces a parcel check.
References
More from Grundy County: browse every local note for the county.
Last checked against the sources above: June 15, 2026.