Blog · October 14, 2026 · New York
The St. Lawrence County Flood Zone Map: a New York guide
FEMA's free flood maps and the St. Lawrence County parcel viewer, used together for property near Brasher.
Main page: St. Lawrence County, NY GIS & Parcel Viewer (official map link, St. Lawrence County facts and neighboring maps).
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The St. Lawrence County flood zone map question tends to arrive at a bad moment: a lender's letter, an insurance quote, or a permit counter in Clare. You can check it yourself for any Clare address in a few minutes.
Next: FEMA's search tool, the zone labels you'll see for St. Lawrence County, and how the parcel record confirms which tract you're on.
Where to see the official St. Lawrence County flood zone map
The authoritative source for a St. Lawrence County flood zone map is FEMA, so begin at the FEMA Flood Map Service Center. Search returns the effective FIRM panel for the spot in St. Lawrence County, plus any pending changes FEMA has posted. On acreage outside Canton, try FEMA's National Flood Hazard Layer viewer, which displays how much of a county parcel sits inside the zone. Next, the NYS Tax Parcels Public layer in ArcGIS Map Viewer confirms which St. Lawrence County parcel you're looking at. Match the St. Lawrence County lines and acreage to the FEMA view, since flood maps don't draw property lines in detail.
Finding the tract on the St. Lawrence County map
For St. Lawrence County, the free public parcel layer is state-run: open the NYS Tax Parcels Public layer in ArcGIS Map Viewer and pan to Brasher. Use the search box for an address in Colton or a parcel number, or simply zoom in and click a property near Brasher. Our St. Lawrence County, NY page keeps the official link and the maps next door to Brasher in one place.
What the flood zone letters mean
Any St. Lawrence County parcel shaded as Zone A, AE, AH or AO sits in what FEMA calls a Special Flood Hazard Area, defined by a 1-percent annual chance of being flooded. Where a St. Lawrence County tract displays Zone AE, there's a base flood elevation to compare a building against; in Zone A there is not one. If a St. Lawrence County parcel displays shaded Zone X, it sits in the moderate band between the 100-year and 500-year floods. Clear, unshaded X near Canton is outside the 500-year floodplain.
Waterfront parcels near Clare
In St. Lawrence County, look closest at tracts along Oswegatchie River, Cranberry Lake and Lake Ozonia. Lines on those St. Lawrence County parcels commonly follow the water, so part of the tract can be mapped as high risk. A creek near Clare that displays no detailed zone, which is why it's worth walking the ground after a heavy rain.
Seller questions about flood history
Request any past flood claims history for a St. Lawrence County property before closing; it tells you more than the map alone. Then call an insurance agent who writes policies around Clare and get a quote using the zone and the county parcel address.
When the map affects a deal
Here's why the zone matters at a closing in Canton. When a structure near Clare falls inside an A or V zone and carries a federally backed mortgage, flood insurance is mandatory under the Flood Disaster Protection Act, wherever the community joins the NFIP. Outside the A zones around Clare, coverage is optional, although some lenders require it anyway. Where a structure near Canton looks higher than the shading suggests, the landowner can ask FEMA for a Letter of Map Amendment (LOMA), typically backed by an elevation certificate from a surveyor who works in the county. Adding on to a house near Clare inside the zone commonly requires a permit and an elevation check, so call the county or the town office in Canton before work starts.
St. Lawrence County flood zones questions
Is Zone AE near Canton high risk?
Zone AE on a lot in De Peyster is a mapped 100-year floodplain with a base flood elevation, so mandatory insurance rules apply to federally backed mortgages.
What does 100-year flood mean for St. Lawrence County land?
No, ground around De Peyster mapped that way has a 1-percent chance of flooding every year, not a once-a-century schedule.
Who prepares an elevation certificate for a house in De Peyster?
A licensed surveyor or engineer prepares it, and the building office serving De Peyster may already have one on file for newer construction.
How can I check a St. Lawrence County, NY flood zone?
Look it up at FEMA's Flood Map Service Center, then match the parcel lines in the NYS Tax Parcels Public layer in ArcGIS Map Viewer; for land near Canton, a zone starting with A or V is high risk.
Can I build in a flood zone in St. Lawrence County?
Often, but local floodplain rules apply; ask the county or town building office in De Peyster before you buy.
Open the official St. Lawrence County, NY parcel map St. Lawrence County 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.