Blog · October 14, 2026 · California
Reading the Foster City Plat Map for a lot
Lots in Foster City trace back to recorded plats filed with the county.
Main page: San Mateo County, CA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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If a legal description for land in Foster City cites a lot number, look up the Foster City plat map it refers to. This Foster City guide covers: where plats are filed, plat versus tax map, and the details that matter to buyers.
The Foster City plat map: start here
For land around Redwood City, the deed or parcel record often names the subdivision and plat reference; that makes the request quick.
Pulling up a parcel
Lots and tracts near Hillsborough are published on the San Mateo County parcel viewer, which opens without registering. When a rural tract has no street number, pan along the nearest road until the lines appear, then click inside the one you want, which applies near Hillsborough as much as anywhere. For property near Redwood City, the parcel card typically gives the owner of record, assessed acreage, a parcel ID and in many cases the last transfer.
Metes and bounds instead
Acreage around San Carlos outside a subdivision may have no plat at all; look for a recorded survey for land near Belmont.
A word on accuracy
Listed acreage is a tax-roll number; just a licensed surveyor sets the real corners on land around Hillsborough. If you're looking near Hillsborough, records update in batches, so a deed recorded last month might lag behind.
Which office to call
Recorded documents for a parcel near Hillsborough sit in the index kept by the County Recorder, sometimes only in person. Zoning, permits and septic questions near San Carlos need the planning or permitting office, and the answer depends on jurisdiction.
City limits and county records
Foster City is part of San Mateo County, California, and the county assessor maps its lots. With a lot near Redwood City, City or town hall handles matters such as zoning, permits and utilities within town limits, while the county keeps the tax map. Land beyond the town limits out by San Carlos often follows county rules, not municipal ones.
The paper trail behind a parcel
When the details count, get the recorded deed from the County Recorder; the parcel map near San Carlos only summarizes it. For property near San Carlos, have ready the instrument number shown in the record panel to skip a name search.
Using it on a phone
Most viewers work in a phone browser, handy when you're parked on a road near San Carlos, though signal can drop in rural spots. A printout of the tract near San Mateo keeps working without signal.
Plat map vs. parcel map
When the two disagree for a lot near Belmont, go with the plat and a surveyor's work.
Amended plats
Lots near San Mateo can be combined or reconfigured by a replat, search the index for replats of the same subdivision; vacated streets or alleys also get recorded.
Legal descriptions in California
California is laid out under the Public Land Survey System, so rural legal descriptions near San Carlos cite section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though sections near San Carlos can be irregular. Copy the legal description from the record for the parcel near San Carlos when you talk to a surveyor.
What a plat shows
Utility or drainage strips on a lot in Foster City can block a shed or pool; read the notes on the sheet.
A quick look at the area
Redwood City holds the county offices, where most land records are kept. You'll also find San Mateo, Belmont, and San Carlos, where town lots give way to larger tracts. Roughly 726,353 people live in San Mateo County (Census estimate, 2023) on some 449 square miles. Features like Don Edwards San Francisco Bay National Wildlife Refuge are easy to spot when you zoom out from Redwood City.
Getting a copy
For acreage around San Carlos, many recorder offices offer an online index, while others require a visit or a request; copy fees are usually small.
Next door to San Mateo County
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. A tract near the line by Hillsborough may show up in two county records, so look at the adjacent map as well. For a home near San Mateo, the Platbookmapper state page lists each neighboring county map for California.
Quick answers
Are old plats online for land near San Mateo?
In most cases, older plats near Hillsborough may be on film or paper; call before you visit.
What is a lot and block description in Foster City?
If you're looking near San Mateo, lot and block refer to a numbered lot within a block on a recorded subdivision plat.
Is a plat map a survey for land near Burlingame?
If you're looking near Belmont, a recorded plat is based on a survey, but the GIS map is not; trust the plat when they differ.
How do I get a copy of a plat in Foster City?
Short answer: copies come from the County Recorder, often through an online index; use the plat reference from the deed or parcel record.
How is land described in California deeds in Foster City?
In and around Belmont, deeds use lot and block, metes and bounds or survey descriptions; copy it for any survey or title request.
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.