Blog · October 14, 2026 · California
Mill Valley Plat Map: finding the recorded plat
A recorded plat shows how land near Sausalito was divided into lots.
Main page: Marin County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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When a deed near Corte Madera says lot and block, the Mill Valley plat map is where those numbers come from. What this Mill Valley guide covers: where to request a copy, plat versus tax map, and the details that matter to buyers.
Getting started with the Mill Valley plat map
For land around Sausalito, the deed or parcel record often names the subdivision and plat reference; use it to request a copy.
Getting to the right map
The public parcel map for this area is the Marin County parcel viewer, and no login is needed to use it. For acreage around Sausalito, type a street address, an owner's name or a parcel number, and the viewer zooms to the match. For acreage around Tiburon, the record panel typically gives the owner of record, acreage on the tax roll, the parcel number and often a sale date.
City limits and county records
Mill Valley is part of Marin County, California, and the county assessor maps its lots. For a home near Ross, city or town hall handles things like zoning, permits and utilities within town limits, but the county runs assessment and recording. Lots just outside the town limits near Tiburon usually falls under county rules rather than the town's.
When a parcel crosses a boundary
Marin County meets Contra Costa County, San Francisco County, Solano County, and Sonoma County, all with their own assessor records. Acreage along the edge near Belvedere may show up in two county records, so open the neighboring map before you assume the acreage. For acreage around Larkspur, the Platbookmapper state page links every neighboring county map across California.
Replats and vacations
Lots near Tiburon can be combined or reconfigured by a replat, so check for later filings; vacated streets or alleys also get recorded.
Getting your bearings
San Rafael is the county seat, which is where the courthouse records live. Smaller places on the map include Larkspur, Corte Madera, Ross, and Sausalito. Around 254,407 people call Marin County home (Census Bureau estimate, 2023) spread over about 520 square miles. Places such as San Pablo Bay, San Francisco Bay, and Golden Gate National Recreation Area make handy reference points on the map near Sausalito.
Using it on a phone
Most viewers work in a phone browser, which helps when you're standing on land near Sausalito, but coverage can be spotty out of town. A screenshot of the parcel near Belvedere with its ID is a good backup.
Getting answers from the right desk
Recorded documents for a parcel near Tiburon come from the County Recorder, usually searchable by name or document number. Questions about what you can build around Tiburon need the planning or permitting office, depending on whether the land is inside town limits.
Recorded plat or GIS layer
The tax map on the Marin County parcel viewer is a summary, but the recorded plat is what the deed relies on.
The paper trail behind a parcel
When the details count, request the recorded deed from the County Recorder; the parcel map near Sausalito only summarizes it. Older tracts around Sausalito can trace back through a long string of deeds, so a title company is worth hiring if money is changing hands.
Sections, lots and bearings
California is laid out under the Public Land Survey System, which means a tract near Belvedere is described by section, township and range. A standard section is about one square mile, roughly 640 acres, with 36 sections to a township, though real sections near Sausalito vary in size. Keep the legal description for land near Tiburon for any title or survey request.
Limits of the parcel data
The acreage figure is an assessed number; just a licensed surveyor sets the real boundary on land around Tiburon. If the land is near Belvedere, owner names and values update on a schedule, so a deed recorded last month may not show yet.
Metes and bounds instead
Rural land near Corte Madera that was never subdivided is often described by metes and bounds or survey description; the deed and any recorded survey describe it instead.
Details on the Mill Valley plat map
With a lot near Sausalito, the sheet usually includes lot and block numbers, dimensions and bearings, street rights-of-way and easements.
Requesting the plat
Near Tiburon, some counties put plat images online, otherwise call or visit with the reference; small fees are common.
Frequently asked
What is a replat for land near Sausalito?
Short answer: combining or splitting lots near Ross usually needs a recorded plat change, often with a surveyor's drawing.
Is a plat map a survey near Tiburon?
Near Ross, GIS parcels are tax drawings, and the recorded plat is the legal document; trust the plat when they differ.
What is a lot and block description for land near Belvedere?
Out toward Belvedere, lot and block refer to a numbered lot within a block on a recorded subdivision plat, so pull that plat for dimensions.
Where are historic plats for Mill Valley?
Usually, older plats near Belvedere may be on film or paper, including older subdivisions.
Does the parcel map work on a phone in Mill Valley?
In and around Ross, most viewers run in a mobile browser; screenshots help offline.
Open the official Marin 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.