Blog · October 14, 2026 · Massachusetts
Dukes County Flood Zone Map in Massachusetts
FEMA's free flood maps and the Dukes County parcel viewer, used together for property near Tisbury.
Main page: Dukes County, MA GIS & Parcel Viewer (official map link, Dukes County facts and neighboring maps).
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Is that lot in Oak Bluffs in a flood zone? The Dukes County flood zone map answer comes from FEMA, and it is free to look up. For any tract in Dukes County, Massachusetts, the answer affects insurance, permits and resale.
Below are the FEMA links, a plain reading of the zone labels, notes on where water shapes land around Oak Bluffs, and short answers to common questions.
Where to see the official Dukes County flood zone map
The authoritative source for a Dukes County flood zone map is FEMA, so begin at the FEMA Flood Map Service Center. Download the FIRM panel FEMA lists as effective for that part of Dukes County. For an irregular lot near Oak Bluffs, FEMA's National Flood Hazard Layer viewer draws the zones over aerial imagery, so you can see if the shading reaches a house near Oak Bluffs. Switch to the MassGIS Interactive Property Map and find the same piece of ground near Oak Bluffs. Match the Dukes County lines and acreage to the FEMA view, since flood maps don't draw property lines in detail.
Finding the tract on the Dukes County map
For Dukes County, the free public parcel layer is state-run: open the MassGIS Interactive Property Map and pan to Oak Bluffs. Click any Dukes County parcel near Edgartown to open its record: owner, parcel ID and assessed acreage are most commonly listed. For a backup route to the map covering Oak Bluffs, our Dukes County directory entry keeps the link current.
High, moderate and minimal risk in Dukes County
Any Dukes County parcel shaded as Zone A, AE, AH or AO sits in what FEMA calls a Special Flood Hazard Area, land with a 1-percent chance of flooding in any given year (the base or 100-year flood). Where a Dukes County tract displays Zone AE, there's a base flood elevation to compare a building against; in Zone A there isn't one. Land near Oak Bluffs in shaded X (Zone B on older maps) sits in the moderate band between the 100-year and 500-year floods. Clear, unshaded X near Aquinnah is outside the 500-year floodplain.
Unmapped creeks in Dukes County
A low spot on a Dukes County tract outside any mapped zone, so treat an unmapped channel as a reason to ask questions, not proof the ground stays dry.
A short buyer checklist for Oak Bluffs
For a house near Edgartown, ask the seller for any elevation certificate on file and the current flood insurance declarations page. Then call an insurance agent who writes policies around Oak Bluffs and get a quote using the zone and the county parcel address.
When the map affects a deal
The zone displays up again when a loan on a house near Oak Bluffs is underwritten. If a house near Oak Bluffs falls inside an A or V zone and carries a federally backed mortgage, federal rules call for flood insurance, provided the community near Aquinnah takes part in the National Flood Insurance Program. Outside the A zones around Oak Bluffs, federal rules don't require a policy; pricing a policy for land near Oak Bluffs is still worth a call. Where a structure near Aquinnah looks higher than the shading suggests, FEMA's LOMA process allows a review, most commonly backed by an elevation certificate from a surveyor who works in the county. New construction in a Dukes County Special Flood Hazard Area commonly requires a permit and an elevation check, so call the county or the town office in Aquinnah before work starts.
Quick answers for Dukes County
Do I need a permit to build in the floodplain near Edgartown?
Building in a Special Flood Hazard Area near Edgartown most commonly needs a floodplain permit and may require elevating the structure, so check with the county floodplain administrator.
What is a base flood elevation for a Dukes County property?
On the map covering Edgartown, the BFE is the height floodwater is expected to reach in the 1-percent-annual-chance flood, and it is printed in AE zones.
What does Zone AE mean on a Dukes County flood map?
Zone AE on a lot in Edgartown is a mapped 100-year floodplain with a base flood elevation, so mandatory insurance rules apply to federally backed mortgages.
Who prepares an elevation certificate for a house in Edgartown?
A professional surveyor or engineer prepares it, and the building office serving Edgartown may already have one on file for newer construction.
Does a 100-year floodplain near Chilmark flood only once a century?
Not at all; a Dukes County tract in that zone has a 1-percent chance of flooding every year, not a once-a-century schedule.
Is flood insurance required for a Zone X lot in Edgartown?
FEMA does not require it for a Zone X lot in Edgartown, but coverage is available and some lenders ask for it.
Open the official Dukes County, MA parcel map Dukes 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.