Blog · October 14, 2026 · California
The San Mateo GIS Map and the county parcel viewer
Parcel data for San Mateo comes from the county, and the viewer is free.
Main page: San Mateo County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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For a parcel in or near San Mateo, a look at the San Mateo GIS map gives you lines, owner names and parcel numbers. What this San Mateo guide covers: where that map lives, the fastest ways to search, and what to double-check with records.
Where the San Mateo GIS map lives
Parcel maps here are usually run by the county, not the town, so for San Mateo the go-to is the San Mateo County parcel viewer.
The viewer San Mateo County publishes
Lots and tracts near Belmont appear on the San Mateo County parcel viewer, which opens without registering. For a home near Foster City, type a street address, an owner's name or a parcel number, and the matching parcel lights up. For property near San Carlos, the record panel usually lists the owner of record, assessed acreage, a parcel ID and in many cases the last transfer.
Legal descriptions in California
California follows the Public Land Survey System, so deeds around Hillsborough reference sections and townships. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though corrections make some sections near Hillsborough odd-sized. Write down the legal description for the tract near San Carlos before you request a deed or survey.
Before you lean on the lines
Tax maps are drawn for assessment, not measured on the ground, so a fence near Millbrae often sits a few yards off the line on screen. Out toward Foster City, records update in batches, so a deed recorded last month might lag behind.
A quick look at the area
Redwood City serves as the county seat, where most land records are kept. Other places on the map include Hillsborough, Foster City, Belmont, and Burlingame. Around 726,353 people call San Mateo County home (Census estimate, 2023) across roughly 449 square miles. Features like Don Edwards San Francisco Bay National Wildlife Refuge are easy to spot when you zoom out from San Carlos.
Neighboring parcel maps
San Mateo County meets Alameda County, San Francisco County, Santa Clara County, and Santa Cruz County; every one of them runs a separate parcel map. Acreage along the edge near Burlingame can show up across two assessors' files, so open the neighboring map too. Out toward Hillsborough, the Platbookmapper state page lists every bordering county map for California.
San Mateo and the county around it
San Mateo is part of San Mateo County, California, which means parcel data comes from the county. If the land is near San Carlos, City or town hall handles matters such as zoning, permits and utilities inside its limits, and the county still keeps the parcel and deed records. Acreage past the city limits out by Millbrae usually answers to county rules, not municipal ones.
Where the recorded documents are
The map is an index, not the title: deeds, plats and easements for land near Hillsborough sit with the County Recorder. Long-held tracts around Foster City may sit on several deeds, and a title company can sort it out if money is changing hands.
Search tips
By address works best for lots in San Mateo; owner search often wants the surname first. If the land is near Foster City, searching by parcel number never misses, and it's printed on tax bills.
Printing and saving
Print or screenshot the parcel near San Carlos with its ID visible, which helps later when you ask the assessor or a title company.
Beyond the parcel lines
For acreage around San Carlos, layer lists often include zoning, flood zones, city limits, school districts or contours; not every viewer has them all.
Taking the map into the field
Most viewers work in a phone browser, which helps when you're standing on land near San Carlos, though signal can drop in rural spots. A printout of the tract near San Carlos helps when you meet an owner or agent.
Offices that can help
If the acreage or value on a parcel near Millbrae looks off belong with the County Assessor, since that office keeps the assessment data. Building or septic questions for a lot near San Carlos go to planning, building or health offices, town or county, depending on location.
What the record panel tells you
If sale dates appear, they help gauge the market around San Carlos are a useful starting point; they're not an appraisal.
Browser tips
When the map won't open around Foster City, switch browsers or turn off pop-up blockers; the Platbookmapper county page tracks the current link.
Quick answers
Can I use the San Mateo GIS map for a fence near Millbrae?
For most people, lines near Millbrae can be off by several feet or more; get a survey before a fence.
Where else can I find maps of San Mateo?
Short answer: check the city website or ask city hall; the county viewer remains the main parcel source, especially near East Palo Alto.
What layers does the parcel viewer have around Millbrae?
For land near Millbrae, many viewers offer aerial imagery plus layers like city limits, zoning or flood zones; open the layer list to see what's there.
Do I need an account for the parcel map near Foster City?
Short answer: there's no fee to use the parcel viewer near Hillsborough.
How do I save a parcel from the viewer near East Palo Alto?
Use the print button or a screenshot, and it's worth keeping the parcel ID visible for land near Foster City.
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.