Blog · October 14, 2026 · Pennsylvania
Allegheny County Flood Zone Map: checking a property's flood zone
Flood zones are set by FEMA, and checking one near Monongahela River takes a few minutes.
Main page: Allegheny County, PA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
Platbookmapper is an Amazon Associate. If you buy through an Amazon link on this page, we earn a commission. The link is a product, not the county map.
Before an offer near Aspinwall, look at the Allegheny County flood zone map: FEMA's zone label affects insurance, building rules and resale. Covered here for the county: locating a parcel on FEMA's map, decoding A, AE and X, and pairing it with the county ArcGIS parcel map for land near Aspinwall.
The Allegheny County flood zone map: start here
If you'd rather pan and zoom, open the National Flood Hazard Layer viewer, where zone shading sits over a photo base, which applies near Ohio River as much as anywhere. Vacant ground around Bakerstown can still be found: zoom in from Interstate 376 and click the spot.
The viewer Allegheny County publishes
Begin with the Allegheny County ArcGIS parcel map; it covers every assessed parcel around Allison Park and Clairton. Near Boston, put in a street address, an owner's name or a parcel number, and the matching parcel lights up. On ground around Ohio River, copy the parcel ID while you have it open; every office in the county will want it.
Which office to call
Questions about value or the owner field for land near Avalon belong with the county assessment office, since that office keeps the assessment data. Questions about what you can build around Pittsburgh go to planning, building or health offices, depending on whether the land is inside town limits.
Legal descriptions in Pennsylvania
Tracts outside towns near Baldwin commonly use metes-and-bounds descriptions, a series of courses and distances from a starting point. Platted lots around Baldwin are typically described by lot and block, which is simpler to follow. Copy the legal description from the record for the parcel near Monongahela River when you talk to a surveyor.
Field tips
The parcel map usually runs in a mobile browser, which helps when you're standing on land near Clairton, so load it before you lose signal. A saved image of the lot near McKeesport and its lines keeps working without signal.
What to request from a seller
Ask the seller about past flood claims for the house near Baldwin; getting a quote early keeps the budget honest.
Recorded documents worth pulling
On ground around Pittsburgh, the map is an index, not the title: deeds, subdivision plats and easements for parcels in the county sit with the Recorder of Deeds. For a parcel near Clairton, have ready the document number listed on the parcel record to skip a name search.
Zones on the Allegheny County flood zone map
If the land is near Carnot-Moon, A and V zones mark the Special Flood Hazard Area, meaning a 1% or greater chance of flooding each year. With a lot near Carnot-Moon, minimal risk is not no risk: according to FEMA, floods happen outside mapped zones too.
Limits of the parcel data
The acreage figure is a tax-roll number; only a licensed surveyor sets the real boundary for a parcel near Ohio River. Records update in batches, so a recent sale near Allegheny River may not show yet.
Low spots and local drainage
Low-lying fields near Bakerstown may not have detailed mapping, so ask neighbors about past flooding. Wet ground around Ohio River is a separate issue from flood zones; check the National Wetlands Inventory mapper for a first look.
Parcel lines plus flood zones
FEMA doesn't draw property lines, so check the Allegheny County ArcGIS parcel map too to see exactly which lot near Bakerstown you're looking at.
Next door to Allegheny County
The county borders Armstrong County, Beaver County, Butler County, Washington County, and Westmoreland County; every one of them runs a separate parcel map for land near Bakerstown. A tract near the line by Carnot-Moon may be split in two county records, so check the adjacent map too. On ground around Boston, our state page links each neighboring county map across Pennsylvania.
Getting your bearings
Pittsburgh is the county seat, which is where the courthouse records live. Other places on the map include Clairton, Duquesne, McKeesport, and Aspinwall. Around 1,224,825 people live in this county (Census estimate, 2023) on about 730 square miles, at least around Allegheny River. The county was organized in 1788, which matters when you trace an old farm's title, especially near Aspinwall. Places such as Allegheny River and Monongahela River make handy reference points on the map.
Lenders and permits
For land near Bairdford, an Elevation Certificate from a surveyor helps: it compares the building to the BFE. Building or adding on near Avalon in a mapped zone often needs a floodplain permit; call the permitting office before you plan.
Frequently asked
What is a LOMA around Bairdford?
Good question; FEMA's LOMA process is the usual route when a building near Monongahela River sits above the base flood elevation, and lenders accept the result.
What is a base flood elevation near Ohio River?
The BFE is printed in AE zones on FEMA's map; surveyors near Allison Park use it often.
Is AE a high-risk flood zone near Pittsburgh?
If the land is near Monongahela River, an AE zone has a 1% annual chance of flooding and a base flood elevation; unnumbered A zones don't list one.
Does the county parcel map show flood zones for land near Carnot-Moon?
For most people, the parcel map near Duquesne might show FEMA zones, but FEMA's own map is the official source.
Who keeps deeds for property in Allegheny County?
For land near Bairdford, assessment goes to the county assessment office and deeds to the Recorder of Deeds.
Open the official Allegheny County, PA 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.