Blog · October 14, 2026 · Pennsylvania
Using the Brentwood Zoning Map
A parcel's zoning district shapes building, splitting and business use near Castle Shannon.
Main page: Allegheny County, PA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Ahead of any building plan near Castle Shannon, look at the Brentwood zoning map first: the zoning district can make or break the plan. What this Brentwood guide covers: which office sets the rules for a lot, matching a lot to its zoning district, and the questions that save a wasted trip.
Reading the Brentwood zoning map for one lot
Within municipal limits, zoning usually comes from the municipality, so property inside Brentwood is governed there. Outside those limits, near Dormont or Pleasant Hills, the county may have its own zoning, or none at all; confirm with the county office. The quickest way to tell which applies: ask whether the parcel near Castle Shannon is inside the boundary.
The free map to start with
Go first to the Allegheny County ArcGIS parcel map; it covers each tax parcel from Mount Oliver to Pleasant Hills. For acreage around Castle Shannon, type a street address, an owner's name or a parcel number, and the matching parcel lights up. In and around Pleasant Hills, the record panel typically gives the owner of record, acreage on the tax roll, the parcel number and in many cases the last transfer.
Places you'll see on the map
Pittsburgh serves as the county seat, where most land records are kept. Smaller places on the map include Whitehall, Baldwin, Castle Shannon, and Mount Oliver. Around 1,224,825 people live in Allegheny County (Census estimate, 2023) spread over about 730 square miles. Allegheny County dates to 1788, and some chains of title near Dormont are long. Features like Allegheny River and Monongahela River help you orient on the aerial around Dormont.
Backing up the map with records
The map is an index, not the title: recorded deeds, plats and easements for land near Dormont are filed with the Recorder of Deeds. Closer to Castle Shannon, use the book and page from the tax record so staff can find the deed fast.
On site with the map
Most viewers work in a phone browser, handy when you're parked on a road near Dormont, but coverage can be spotty out of town. A screenshot of the parcel near Castle Shannon with its ID keeps working without signal.
What to ask before you buy
When you call about land near Pleasant Hills, give the parcel number and your intended use; staff can point to the right section of the ordinance. Ask whether a parcel near Whitehall meets current minimum size, because nonconforming lots can carry limits.
Building permits and inspections
Even when zoning allows a use near Whitehall, a building permit is a separate step; septic or sewer and driveway access are often reviewed too.
Which office to call
For assessment questions about property around Whitehall belong with the county assessment office, the office behind the parcel record. Zoning, permits and septic questions near Dormont go to planning, building or health offices, depending on whether the land is inside town limits.
Where Brentwood fits in
Brentwood lies within Allegheny County, Pennsylvania, and the county assessor maps its lots. On ground around Pleasant Hills, city or town hall handles things like zoning, permits and utilities within town limits, while the county keeps the tax map. Lots just outside the town limits toward Whitehall generally follows county rules rather than the town's.
Before you lean on the lines
Parcel lines are drawn for taxes, not surveyed, so the edge of a yard near Baldwin can sit several feet off the line on screen. For a home near Dormont, owner names and values update on a schedule, so a deed recorded last month may not show yet.
How to look up the district
Pull the parcel up on the Allegheny County ArcGIS parcel map, copy its parcel ID, and use it when you ask the planning office near Dormont. Closer to Baldwin, short codes on the map point to a table of rules in the ordinance; don't assume a code means the same thing everywhere.
What the district controls
Out toward Whitehall, the ordinance spells out uses allowed by right, uses needing a permit, and uses not allowed. With a lot near Mount Oliver, overlay districts, such as floodplain, historic or airport zones, can add rules on top of the base district.
Changing what's allowed
When a project near Pleasant Hills falls outside the rules, ask about a variance, a conditional use permit or a rezoning.
Frequently asked
Is land outside Brentwood zoned?
Land beyond Brentwood limits usually follows county rules, if any, so ask the county planning office.
What does a rezoning in Brentwood involve?
The governing body near Whitehall decides after hearings.
What is the zoning on a property near Whitehall?
It depends, but find the parcel near Pleasant Hills on the Allegheny County ArcGIS parcel map, confirm whether it's inside Brentwood limits, then ask that planning office for the district; staff can confirm by phone or email.
Can I get an exception to a setback near Baldwin?
Good question; boards in Brentwood grant variances only when strict rules cause a real hardship; ask staff about the standards.
Is there an app for the parcel map near Whitehall?
If the land is near Whitehall, most viewers run in a mobile browser; screenshots help offline.
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.