Blog · October 14, 2026 · California
Reading the Brentwood Plat Map for a lot
A recorded plat shows how land near Danville was divided into lots.
Main page: Contra Costa County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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When a deed near Clayton says lot and block, you'll need the Brentwood plat map to make sense of it. Covered here for Brentwood: where plats are filed, plat versus tax map, and what to look for on the sheet.
Getting started with the Brentwood plat map
For a subdivision near Danville, the deed usually cites the plat; bring that to the recorder's office or its online index.
Where the parcel data lives
Go first to the Contra Costa County parcel viewer; it includes each assessed parcel from Pittsburg to Danville. When a rural tract has no street number, zoom in from Oakley until the lines appear, then click inside the one you want. For property near Pittsburg, write down the parcel ID from that panel; every office in the county asks for it first.
Metes and bounds instead
Rural land near Pittsburg that was never subdivided is often described by metes and bounds or survey description; the deed and any recorded survey describe it instead.
On site with the map
The parcel map usually runs in a mobile browser, handy when you're parked on a road near Oakley, but coverage can be spotty out of town. A screenshot of the parcel near Oakley with its ID is a good backup.
Backing up the map with records
For anything that matters, get the recorded deed from the County Recorder; the parcel line is a drawing of it, and that holds around Antioch too. If you're looking near Concord, have ready the instrument number listed on the parcel record so staff can find the deed fast.
Neighboring parcel maps
Contra Costa County touches Alameda County, Marin County, Sacramento County, San Francisco County, and San Joaquin County, all with their own assessor records. Acreage along the edge near Concord can be split across two assessors' files, so look at the adjacent map before you assume the acreage. For property near Antioch, the Platbookmapper state page lists each neighboring county map for California.
A quick look at the area
Martinez is the county seat, which is where the courthouse records live. You'll also find Oakley, Antioch, Pittsburg, and Clayton, each with its own cluster of lots. Around 1,155,025 people live in Contra Costa County (Census estimate, 2023) on about 717 square miles. Features like Clayton-Marsh Creek-Greenville Fault, San Pablo Dam Reservoir, and Mount Diablo State Park are easy to spot when you zoom out from Danville.
Sections, lots and bearings
California is laid out under the Public Land Survey System, which means a tract near Clayton is described by section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though real sections near Concord vary in size. Copy the legal description from the record for the parcel near Antioch for any title or survey request.
Amended plats
Lots near Oakley can be combined or reconfigured by a replat, so check for later filings; street vacations show up in the records too.
City limits and county records
Brentwood is part of Contra Costa County, California, so its parcels are on the county's map. For acreage around Clayton, the municipality handles matters such as zoning, permits and utilities for lots inside the boundary, but the county runs assessment and recording. Acreage past the town limits toward Oakley often falls under county rules rather than the town's.
Two different maps
When the two disagree for a lot near Oakley, trust the recorded documents over the GIS layer.
Offices that can help
Deeds, mortgages and recorded plats for land near Danville are with the County Recorder, usually searchable by name or document number. Zoning, permits and septic questions near Danville go to planning, building or health offices, depending on whether the land is inside town limits.
Lots, blocks and easements
On ground around Oakley, the sheet usually includes lot and block numbers, dimensions and bearings, street rights-of-way and easements.
Before you lean on the lines
Tax maps are drawn for assessment, not measured on the ground, so a tree line near Pittsburg may sit several feet off the line on screen. For acreage around Antioch, records update in batches, so a deed recorded last month might lag behind.
Getting a copy
For property near Oakley, many recorder offices offer an online index, while others require a visit or a request; copy fees are usually small.
Frequently asked
Is the Brentwood plat map the same as the county GIS?
Generally, the plat near Clayton is recorded, while the GIS layer is an approximation; trust the plat when they differ.
Who has recorded plats for land near Antioch?
Short answer: the County Recorder keeps recorded plats.
What is a lot and block description near Clayton?
Short answer: it points to a spot on the plat for that subdivision near Antioch, so pull that plat for dimensions.
Do easements show on the plat near Pittsburg?
It depends, but building on an easement near Clayton is generally restricted; read the plat notes.
What's the tax parcel number used for around Antioch?
It's the number the County Assessor uses to track a tract near Antioch, and it's on the record panel and tax bills.
Open the official Contra Costa County, CA 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.