Blog · October 14, 2026 · California
Using the San Anselmo Plat Map
A recorded plat shows how land near Corte Madera 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 Larkspur says lot and block, look up the San Anselmo plat map it refers to. Covered here for San Anselmo: where plats are filed, how a plat differs from a parcel map, and the details that matter to buyers.
Getting started with the San Anselmo plat map
For land around Ross, the deed usually cites the plat; bring that to the recorder's office or its online index.
The free map to start with
Parcels around San Rafael can be looked up on the Marin County parcel viewer, a viewer that needs no account. If you're looking near Mill Valley, put in a street address, an owner's name or a parcel number, and the viewer zooms to the match. Closer to Novato, a pop-up or side panel typically gives the owner of record, assessed acreage, the parcel number and often a sale date.
Which office to call
Questions about value or the owner field for land near Mill Valley belong with the County Assessor, which maintains the tax roll. Building or septic questions for a lot near Novato go to planning, building or health offices, town or county, depending on location.
How land is described here
California is laid out under the Public Land Survey System, so rural legal descriptions near Corte Madera cite section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though sections near Novato can be irregular. Keep the legal description for land near San Rafael for any title or survey request.
San Anselmo, CA: the basics
San Anselmo lies within Marin County, California, which means parcel data comes from the county. On ground around Novato, city or town hall handles matters such as zoning, permits and utilities within town limits, and the county still keeps the parcel and deed records. Acreage past the town limits toward Novato generally answers to county rules instead.
Where the recorded documents are
For anything that matters, pull the recorded deed through the County Recorder; the parcel map near Larkspur only summarizes it. Older tracts around Ross may trace back through many deeds, so a title company can sort it out on a real sale.
Two different maps
The Marin County parcel viewer draws parcels for taxes, but the recorded plat is what the deed relies on.
When a parcel crosses a boundary
Marin County borders Contra Costa County, San Francisco County, Solano County, and Sonoma County; every one of them runs a separate parcel map. Ground near Ross that runs to the line can show up across two assessors' files, so look at the adjacent map as well. For acreage around Corte Madera, the Platbookmapper state page lists each bordering county map for California.
What a plat shows
Utility or drainage strips on a lot in San Anselmo limit where you can build or fence; check the plat notes and any covenants.
Marin County in a few facts
San Rafael is the county seat, which is where the courthouse records live. You'll also find Ross, Larkspur, and Corte Madera, where town lots give way to larger tracts. About 254,407 people call Marin County home (Census estimate, 2023) spread over about 520 square miles. Features like San Pablo Bay, San Francisco Bay, and Golden Gate National Recreation Area make handy reference points on the map near San Rafael.
When there's no plat
Acreage around Novato outside a subdivision may have no plat at all; the deed and any recorded survey describe it instead.
Ordering the San Anselmo plat map
For a parcel near San Rafael, many recorder offices offer an online index, while others require a visit or a request; copy fees are usually small.
Limits of the parcel data
The acreage figure is an estimate; only a licensed surveyor establishes the real boundary for a parcel near Mill Valley. If you're looking near Mill Valley, owner names and values update on a schedule, so a deed recorded last month may not show yet.
Amended plats
Lots near Novato can be combined or reconfigured by a replat, search the index for replats of the same subdivision; vacated streets or alleys also get recorded.
On site with the map
The parcel map usually runs in a mobile browser, useful out on a road near Novato, though signal can drop in rural spots. A printout of the tract near Corte Madera keeps working without signal.
San Anselmo: common questions
Is a plat map a survey in San Anselmo?
On ground around Larkspur, a recorded plat is based on a survey, but the GIS map is not; trust the plat when they differ.
What is a replat around Corte Madera?
Good question; lot splits in San Anselmo go through the planning office; ask staff about the process.
Are old plats online in San Anselmo?
Older plats near Larkspur may be on film or paper; call before you visit.
What do the dashed lines on a plat mean near Novato?
It depends, but building on an easement near Novato is generally restricted; ask planning staff if unsure.
Why don't the lines match my fence near Ross?
The map near San Rafael is approximate, so a fence may sit off the line
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.