Blog · October 14, 2026 · California
Redwood City Plat Map: finding the recorded plat
A recorded plat shows how land near Atherton was divided into lots.
Main page: San Mateo County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Buying a lot in a subdivision near East Palo Alto? What you want is the Redwood City plat map, because the recorded plat shows how the land was divided. This Redwood City guide covers: where to request a copy, how a plat differs from a parcel map, and what to look for on the sheet.
Tracking down the Redwood City plat map
For land around East Palo Alto, look for the plat book reference on the parcel record; use it to request a copy.
The viewer San Mateo County publishes
Your first stop is the San Mateo County parcel viewer; it maps every assessed parcel around Belmont and Menlo Park. For a tract near Belmont, enter a street address, an owner's name or a parcel number, then pick the result to center the map on it. For a tract near East Palo Alto, the record panel normally shows the owner of record, assessed acreage, a parcel ID and sometimes recent sales.
On site with the map
Most viewers work in a phone browser, handy when you're parked on a road near Atherton, though signal can drop in rural spots. A screenshot of the parcel near Menlo Park with its ID helps when you meet an owner or agent.
Redwood City, CA: the basics
The city lies within San Mateo County, California, which means parcel data comes from the county, especially near Burlingame. Redwood City is also the county seat, which puts the County Recorder close by. Local government in Redwood City handles matters such as zoning, permits and utilities within town limits, while the county keeps the tax map. Lots just outside the city limits toward Foster City generally falls under county rules, not municipal ones.
Plat map vs. parcel map
Where lines don't match in Redwood City, trust the recorded documents over the GIS layer.
Metes and bounds instead
Acreage around Menlo Park outside a subdivision is often described by metes and bounds or survey description; the deed and any recorded survey describe it instead.
Limits of the parcel data
Parcel lines are drawn for taxes, not surveyed, so a fence near Menlo Park may sit some distance off the line on screen. On ground around Menlo Park, owner names and values update on a schedule, so a deed recorded last month might lag behind.
Reading the plat sheet
Utility or drainage strips on a lot in Redwood City limit where you can build or fence; read the notes on the sheet.
Next door to San Mateo County
San Mateo County borders Alameda County, San Francisco County, Santa Clara County, and Santa Cruz County, all with their own assessor records. Acreage along the edge near East Palo Alto may show up across two assessors' files, so check the neighboring map too. Closer to East Palo Alto, our state page lists each neighboring county map for California.
Getting answers from the right desk
If the acreage or value on a parcel near Atherton looks off go to the County Assessor, since that office keeps the assessment data. Building or septic questions for a lot near Atherton go to planning, building or health offices, town or county, depending on location.
Reading the legal description
California uses the Public Land Survey System, which means a tract near San Carlos 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 corrections make some sections near Foster City odd-sized. Write down the legal description for the tract near Menlo Park before you request a deed or survey.
Amended plats
An amended plat may change lots around Foster City, so check for later filings; vacated streets or alleys also get recorded.
Ordering the Redwood City plat map
On ground around San Carlos, some counties put plat images online, otherwise call or visit with the reference; small fees are common.
San Mateo County in a few facts
Redwood City is the county seat, where most land records are kept. You'll also find San Carlos, Foster City, Atherton, and Menlo Park, where town lots give way to larger tracts. About 726,353 people live in San Mateo County (Census Bureau estimate, 2023) spread over roughly 449 square miles. Features like Don Edwards San Francisco Bay National Wildlife Refuge make handy reference points on the map near Atherton.
Where the recorded documents are
The map is an index, not the title: deeds, plats and easements for land near Atherton sit with the County Recorder. Older tracts around Menlo Park may trace back through a long string of deeds, so a title company can sort it out if money is changing hands.
Redwood City: common questions
How far back do plats go near Atherton?
Short answer: older plats near Menlo Park may be on film or paper, including older subdivisions.
What is a replat in Redwood City?
For most people, combining or splitting lots near Atherton usually needs a recorded plat change; ask staff about the process.
Is a plat map a survey for land near East Palo Alto?
For most people, the plat near Belmont is recorded, while the GIS layer is an approximation.
What do the dashed lines on a plat mean around Foster City?
If the land is near Belmont, dashed lines often mark easements or building lines, so check before you build.
Is the parcel map a survey around San Carlos?
The map near Atherton is approximate; a survey sets the real corners
Open the official San Mateo 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.