Blog · October 14, 2026 · Iowa
Union County Flood Zone Map: checking a property's flood zone
Flood zones are set by FEMA, and checking one near Shannon City takes a few minutes.
Main page: Union County, IA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Weighing a property around Afton? A quick look at the Union County flood zone map shows whether the lot falls inside a mapped floodplain, and no account is needed. In this Union County guide: the free FEMA tools, what each zone label means, when insurance is required and how to challenge a map that looks wrong.
Checking the Union County flood zone map step by step
Start with FEMA's Flood Map Service Center: type an address near Cromwell, then open the map view for that panel. Vacant ground around Shannon City can still be found: pan from the closest town and click the spot.
Getting to the right map
Begin with the Union County Beacon site; it covers each tax parcel in the county, Cromwell included. For land near Kent, put in a street address, an owner's name or a parcel number, and the matching parcel lights up. For land near Creston, save the parcel ID while you have it open; each clerk in the county will want it.
Taking the map into the field
Most viewers work in a phone browser, useful out on a road near Thayer, so load it before you lose signal. A saved image of the lot near Lorimor and its lines helps when you meet an owner or agent.
What the zone letters mean
On ground around Cromwell, any A or V zone are Special Flood Hazard Areas, land with a 1-percent chance of flooding in any year. For a tract near Afton, a shaded X area marks moderate flood hazard, between the 1% and 0.2% annual chance floods; plain X, or C on older maps, is minimal risk.
A word on accuracy
For acreage around Talmage, listed acreage is an assessed number; just a licensed surveyor can set the real corners on the ground. If the land is near Arispe, owner names and values update on a schedule, so a deed recorded last month can take weeks to appear.
Lining it up with the parcel map
FEMA's map shows zones but not ownership, so pair it with the Union County Beacon site to see exactly which lot near Creston you're looking at.
What to request from a seller
With a lot near Lorimor, request for any Elevation Certificate before closing; getting a quote early avoids surprises.
The paper trail behind a parcel
For a home near Talmage, the map is an index, not the title: deeds, subdivision plats and easements for parcels in the county sit with the County Recorder. Long-held tracts around Kent may trace back through many deeds, and a title company can sort it out before a purchase.
Land on the county line
Union County meets Adair County, Adams County, Clarke County, Decatur County, and Madison County; every one of them runs a separate parcel map. Acreage along the edge near Cromwell may be split in two county records, so look at the neighboring map too. Around Afton, the Platbookmapper state page links each neighboring county map for Iowa.
Places you'll see on the map
Creston serves as the county seat, where most land records are kept. You'll also find Afton, Arispe, Cromwell, and Lorimor, each with its own cluster of lots. Around 11,906 people call Union County home (Census estimate, 2023) across roughly 424 square miles. The county was organized in 1851, and some chains of title near Talmage are long.
Which office to call
Deeds, mortgages and recorded plats for land near Cromwell come from the County Recorder, often with an online index. Building or septic questions for a lot near Creston are for the local planning and health departments, depending on whether the land is inside town limits.
What a flood zone means for a buyer
For a structure inside an A or V zone and the loan is federally backed or regulated, flood insurance is generally required where the community participates in the National Flood Insurance Program, for land near Afton included. Remodeling a house in a zone near Creston can trigger elevation rules; call the permitting office early.
Beyond the mapped zones
Low-lying fields near Thayer may not have detailed mapping, so ask neighbors about past flooding. Wet ground around Thayer is a separate issue from flood zones; the National Wetlands Inventory mapper shows mapped wetlands.
Union County: common questions
What is a base flood elevation around Afton?
It depends, but a BFE near Afton tells builders how high the lowest floor should be; local rules may require building above it.
What is a LOMA in Union County?
Short answer: you can ask FEMA for a LOMA if surveyed elevations show the building near Kent is above the BFE, and lenders accept the result.
Is AE a high-risk flood zone for land near Shannon City?
In and around Arispe, AE is a Special Flood Hazard Area with a published base flood elevation; unnumbered A zones don't list one.
How often are flood maps updated near Creston?
For most people, zones near Arispe can shift when FEMA updates a panel; check the effective date on the panel.
Is the parcel map a survey near Afton?
No; boundary questions near Kent need a licensed surveyor; a survey sets the real corners
Open the official Union County, IA parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.